@article{palmer_kirkwood_gross_steer_newman_johnson_2019, title={A Bright Future for Integrated Magnetics}, volume={20}, ISSN={["1557-9581"]}, DOI={10.1109/MMM.2019.2904381}, abstractNote={Magnetic materials and components play a critical role in the technology we use in our daily lives. Many things, from electric motors to data storage, radar, and communication systems, rely on the properties of magnetic materials. The inherent physics of magnetic materials provides us with signal processing and control that either cannot be replicated or is difficult to replicate with electric-field-based devices alone.}, number={6}, journal={IEEE MICROWAVE MAGAZINE}, author={Palmer, William and Kirkwood, David and Gross, Steve and Steer, Michael and Newman, Harvey S. and Johnson, Scooter}, year={2019}, month={Jun}, pages={36–50} }
@article{harvey_steer_rappaport_2019, title={Exploiting High Millimeter Wave Bands for Military Communications, Applications, and Design}, volume={7}, ISSN={["2169-3536"]}, DOI={10.1109/ACCESS.2019.2911675}, abstractNote={Military communications networks can leverage much of the millimeter-wave (mm-wave) technology being investigated and developed for 5G cellular but require special attention to the unique military requirements. This paper highlights the special communications' requirements of specific military local area networks and discusses how higher band mm-wave technology can contribute to high data rates and simultaneously achieve covertness. Adaptive tuning for varying atmospheric absorption meets the military requirements for quickly adjusting covert communication zones to accommodate potentially rapid movements of network nodes, dynamic output power constraints, and changing environmental conditions.}, journal={IEEE ACCESS}, author={Harvey, James F. and Steer, Michael B. and Rappaport, Theodore S.}, year={2019}, pages={52350–52359} }
@book{steer_2019, title={Fundamentals of Microwave and RF Design}, ISBN={9781469656892}, url={http://dx.doi.org/10.5149/9781469656892_Steer}, DOI={10.5149/9781469656892_Steer}, publisher={NC State University}, author={Steer, Michael}, year={2019}, month={Jul} }
@misc{steer_2019, title={Microwave and RF Design: Amplifiers and Oscillators, Volume 5}, ISBN={9781469656991}, url={http://dx.doi.org/10.5149/9781469656991_Steer}, DOI={10.5149/9781469656991_Steer}, publisher={NC State University}, author={Steer, Michael}, year={2019}, month={Jul} }
@misc{steer_2019, title={Microwave and RF Design: Modules, Volume 4}, ISBN={9781469656977}, url={http://dx.doi.org/10.5149/9781469656977_Steer}, DOI={10.5149/9781469656977_Steer}, publisher={NC State University}, author={Steer, Michael}, year={2019}, month={Jul} }
@misc{steer_2019, title={Microwave and RF Design: Networks, Volume 3}, ISBN={9781469656953}, url={http://dx.doi.org/10.5149/9781469656953_Steer}, DOI={10.5149/9781469656953_Steer}, publisher={NC State University}, author={Steer, Michael}, year={2019}, month={Jul} }
@misc{steer_2019, title={Microwave and RF Design: Radio Systems, Volume 1}, ISBN={9781469656915}, url={http://dx.doi.org/10.5149/9781469656915_Steer}, DOI={10.5149/9781469656915_Steer}, publisher={NC State University}, author={Steer, Michael}, year={2019}, month={Jul} }
@misc{steer_2019, title={Microwave and RF Design: Transmission Lines, Volume 2}, ISBN={9781469656939}, url={http://dx.doi.org/10.5149/9781469656939_Steer}, DOI={10.5149/9781469656939_Steer}, publisher={NC State University}, author={Steer, Michael}, year={2019}, month={Jul} }
@article{wang_kilgore_steer_adams_2018, title={Characterization of Intermodulation Distortion in Reconfigurable Liquid Metal Antennas}, volume={17}, ISSN={["1548-5757"]}, DOI={10.1109/lawp.2017.2786078}, abstractNote={The intermodulation distortion produced by passive and tunable liquid metal (LM) antennas is investigated. Four kinds of monopoles, including a passive copper monopole, a varactor-tuned copper monopole, a passive LM monopole, and a tunable LM monopole using electrochemically controlled capillarity (ECC), are compared for their linearity and power-handling capabilities. Linearity is assessed using a two-tone distortion test, in which two fundamental tones close in frequency result in third-order intermodulation tones at frequencies above and below the original tones separated by the frequency difference. The passive LM monopole has comparable linearity to the passive copper monopole, while the linearity of the ECC-tuned LM monopole is at least 40 dB better than that of the active varactor monopole. The reconfigurable LM antenna also handles higher power (31 dBm) before failure than does the active varactor-tuned antenna (24 dBm).}, number={2}, journal={IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS}, author={Wang, Meng and Kilgore, Ian M. and Steer, Michael B. and Adams, Jacob J.}, year={2018}, month={Feb}, pages={279–282} }
@article{chen_zirky_steer_2018, title={Microwave Excitation of Crystalline Energetic Composites}, volume={6}, ISSN={["2169-3536"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85044751997&partnerID=MN8TOARS}, DOI={10.1109/access.2018.2810265}, abstractNote={Hotspots produced by microwaves radiating into an energetic composite of RDX crystals and an estane binder are examined using transient electromagnetic (EM) and coupled EM-thermal analyses. Hotspots, localized regions where energetic activity is likely to initiate, manifest as regions of peak electric field or high temperature. Stress caused by these high fields and temperatures may result in molecular breakdown, creating a chain reaction leading to the release of chemical energy via deflagration (burning and melting) in the absence of a mechanical shock wave. High peak electric fields up to three times higher than the incident field result from subwavelength scattering and occur near crystalline surfaces while peak temperatures occur in the binder, with both generally coinciding at the binder-RDX interface. Abstractions enable materials to be modeled with crystals having an average characteristic dimension of 100 μm. With an incident field of 1 MV/m the peak electric field in the composite was 2.9 MV/m and peak temperature increased by 75 K in the binder and 65 K in the RDX after 3.7 ms. The RDX fill factor of the composite was 37%, typical of an improvised explosive.}, journal={IEEE ACCESS}, author={Chen, Michael and Zirky, Mohammed A. and Steer, Michael B.}, year={2018} }
@article{ansuinelli_schuchinsky_frezza_steer_2018, title={Passive Intermodulation Due to Conductor Surface Roughness}, volume={66}, ISSN={["1557-9670"]}, DOI={10.1109/tmtt.2017.2784817}, abstractNote={The physical mechanism of the experimentally observed dependence of passive intermodulation (PIM) in printed circuits on conductor surface roughness is studied. It is shown that electrothermal (ET) nonlinearity, arising due to heating of imperfect conductors by high-power carriers in a multicarrier system, is correlated with conductor surface roughness and has a unique signature. Carriers modulate the conductor resistivity, skin depth, and surface impedance which generate PIM products. The detailed analysis demonstrates that ET-PIM depends on the conductor resistivity, shape, and roughness profile and also on the electric and thermal properties of the substrate. Their effects on PIM are illustrated by examples of uniform microstrip lines with different conductor and substrate materials, and periodically perturbed and meandered microstrip lines.}, number={2}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Ansuinelli, Paolo and Schuchinsky, Alexander G. and Frezza, Fabrizio and Steer, Michael B.}, year={2018}, month={Feb}, pages={688–699} }
@article{chen_steer_2017, title={Abstracted Random Mediums for Electromagnetic Hotspot Observation in Finite-Difference Time-Domain Simulation}, volume={65}, ISSN={["1557-9670"]}, DOI={10.1109/tmtt.2016.2640951}, abstractNote={Microwave excitation of energetic materials can remotely incite ignition and deflagration. While this has been experimentally observed, the underlying principles are not well understood due to the complexity of analytical solutions. Further complicating understanding is the sensitivity of the effect to geometry and the difficulty of creating simulation environments representative of realistic materials. Manageable analysis requires abstractions, and here abstractions ranging from regularly arranged spheres and cubes to randomly arranged spheres, cubes, and arbitrarily shaped crystals are examined. The randomly arranged cube model provides acceptable prediction of thermal and peak electric field hotspots while having manageable computational complexity. The hotspots resulting from multiple subwavelength scattering occur inside the body of the energetic material and are localized in time and space having spans that are a few percent or less of the period and wavelength of pulsed electromagnetic excitation.}, number={5}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Chen, Michael and Steer, Michael B.}, year={2017}, month={May}, pages={1873–1879} }
@inproceedings{chen_steer_zikry_2017, title={Significance of randomness in establishing hotspots in crystals}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85019680119&partnerID=MN8TOARS}, DOI={10.1109/secon.2017.7925394}, abstractNote={Microwave scattering in random mediums is known to result in localized energy concentrations known as hotspots. However, the mechanics behind this effect are not well understood. Abstractions are needed to manage the complexity required to develop understanding through simulation and lead to the establishment of the parameters for a microwave system to neutralize energetic materials. Here, two random contributions of rotation and translation are separately simulated. It is observed that the individual effects both contribute to localization, and the combined effect is greater than the sum of the individuals.}, booktitle={Southeastcon 2017}, author={Chen, M. and Steer, M. B. and Zikry, Mohammed}, year={2017} }
@article{steer_2016, title={2016 Fellows Elevation and Recognition}, volume={17}, ISSN={["1557-9581"]}, DOI={10.1109/mmm.2016.2579824}, number={9}, journal={IEEE MICROWAVE MAGAZINE}, author={Steer, Michael}, year={2016}, month={Sep}, pages={45–57} }
@article{kozlov_shitvov_schuchinsky_steer_2016, title={Passive Intermodulation of Analog and Digital Signals on Transmission Lines With Distributed Nonlinearities: Modelling and Characterization}, volume={64}, ISSN={["1557-9670"]}, DOI={10.1109/tmtt.2016.2550046}, abstractNote={Passive intermodulation (PIM) often limits the performance of communication systems with analog and digitally modulated signals and especially of systems supporting multiple carriers. Since the origins of the apparently multiple physical sources of nonlinearity causing PIM are not fully understood, the behavioral models are frequently used to describe the process of PIM generation. In this paper, a polynomial model of memoryless nonlinearity is deduced from PIM measurements of a microstrip line with distributed nonlinearity with two-tone CW signals. The analytical model of nonlinearity is incorporated in Keysight Technology's ADS simulator to evaluate the metrics of signal fidelity in the receive band for analog and digitally modulated signals. PIM-induced distortion and cross-band interference with modulated signals are compared with those with two-tone CW signals. It is shown that conventional metrics can be applied to quantify the effect of distributed nonlinearities on signal fidelity. It is found that the two-tone CW test provides a worst-case estimate of cross-band interference for two-carrier modulated signals, whereas, with a three-carrier signal, PIM interference in the receive band is noticeably overestimated. The simulated constellation diagrams for QPSK signals demonstrate that PIM interference exhibits the distinctive signatures of correlated distortion and this indicates that there are opportunities for mitigating PIM interference and that PIM interference cannot be treated as noise. One of the interesting results is that PIM distortion on a transmission line results in asymmetrical regrowth of output PIM interference for modulated signals.}, number={5}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Kozlov, Dmitry S. and Shitvov, Alexey P. and Schuchinsky, Alexander G. and Steer, Michael B.}, year={2016}, month={May}, pages={1383–1395} }
@article{kilgore_kabiri_kane_steer_2016, title={The Effect of Chaotic Vibrations on Antenna Characteristics}, volume={15}, ISSN={["1548-5757"]}, DOI={10.1109/lawp.2015.2503264}, abstractNote={The radio signal transmitted from a vibrating antenna is modulated producing spectral content that can interfere with a nearby receiver. The additional spectral content is centered at the transmitted RF signal, and with chaotic vibrations, the spectrum has significant content beyond the fundamental frequency of vibration. Thus, the effect of vibration on co-site interference is much greater than expected. A controlled experiment using a monopole antenna driven at 900 MHz and vibrating at 150 Hz has significant RF spectral content extending to 5 kHz.}, journal={IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS}, author={Kilgore, Ian M. and Kabiri, Shabir A. and Kane, Andrew W. and Steer, Michael B.}, year={2016}, pages={1242–1244} }
@article{steer_2016, title={The MTT-S Publications Committee-Advancing Research}, volume={17}, ISSN={["1557-9581"]}, DOI={10.1109/mmm.2016.2580325}, number={9}, journal={IEEE MICROWAVE MAGAZINE}, author={Steer, Michael}, year={2016}, month={Sep}, pages={80–81} }
@article{ma_steer_jiang_2015, title={An acoustic filter based on layered structure}, volume={106}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.4915100}, DOI={10.1063/1.4915100}, abstractNote={Acoustic filters (AFs) are key components to control wave propagation in multi-frequency systems. We present a design which selectively achieves acoustic filtering with a stop band and passive amplification at the high- and low-frequencies, respectively. Measurement results from the prototypes closely match the design predictions. The AF suppresses the high frequency aliasing echo by 14.5 dB and amplifies the low frequency transmission by 8.0 dB, increasing an axial resolution from 416 to 86 μm in imaging. The AF design approach is proved to be effective in multi-frequency systems.}, number={11}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Ma, Jianguo and Steer, Michael B. and Jiang, Xiaoning}, year={2015}, month={Mar}, pages={111903} }
@article{liu_inal_steer_virdee_2015, title={Microfabrication of conical microfunnels for drug delivery applications}, volume={10}, ISSN={1750-0443}, url={http://dx.doi.org/10.1049/MNL.2014.0659}, DOI={10.1049/MNL.2014.0659}, abstractNote={A cost-effective fabrication methodology for the mass production of conical microfunnels for drug delivery applications is presented. The fabrication methodology originates from a technique previously used for fabricating suspended or hollow microstructures. The process comprises six stages: in stage 1, a UV-opaque resin substrate is formed by mixing photocurable SU-8 with a UV-opaque impurity; in stage 2, an embossing stamp with an array of microrods is fabricated; in stage 3, the upper surface of the UV-opaque resin substrate (from the first stage) is mechanically deformed by stamping with the embossing stamp from stage 2; in stage 4, the regions in which microfunnels are photolithographically defined are selectively exposed to UV light; in stage 5, the wafer from stage 4 is subjected to heat and then developed in 1-methoxy-2-propanol acetate; finally, a hole on the tip of each microfunnel is formed by dry etching with oxygen plasma. The sharpness of the funnel tips can be flexibly adjusted by changing the stroke speed of the stamping in stage 3. The overall process can be carried out photolithographically with conventional photolithographic equipment. Using the proposed fabrication methodology, a matrix of polymeric microfunnels tapering from the base measuring 300 μm to the tip measuring 50 μm over a funnel height of 100 μm has been fabricated. Each fabricated microfunnel features a wide base and a sharp tip so that it has sufficient mechanical strength and sharpness to pierce the human skin. The conical geometry used in this study had a volume in excess of 24.4 nl.}, number={7}, journal={Micro & Nano Letters}, publisher={Institution of Engineering and Technology (IET)}, author={Liu, L.W.Y. and Inal, J. and Steer, M.B. and Virdee, B.S.}, year={2015}, month={Jul}, pages={355–357} }
@article{wilkerson_kilgore_gard_steer_2015, title={Passive Intermodulation Distortion in Antennas}, volume={63}, ISSN={["1558-2221"]}, DOI={10.1109/tap.2014.2379947}, abstractNote={An analytic formulation of passive intermodulation distortion (PIM) in antennas is presented for PIM introduced by electro-thermal modulation of conductivity by current-related losses. A silver rectangular patch antenna was fabricated using a sapphire substrate isolating the thermal process from other possible sources. Two-tone testing at 990 MHz using a sweep of the tone separation from 3 Hz to 100 kHz is reported. Both transmitted and reflected PIM are characterized using a high dynamic range two-tone test system incorporating an analog canceler achieving a dynamic range of 125 dB at 1-Hz tone separation for reflection measurements, and 100 dB at 10-Hz tone separation for transmission measurements with each tone set to 32.3 dBm.}, number={2}, journal={IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, author={Wilkerson, Jonathan R. and Kilgore, Ian M. and Gard, Kevin G. and Steer, Michael B.}, year={2015}, month={Feb}, pages={474–482} }
@article{heinz_brennan_steer_melber_cua_2015, title={Phase Response of High to Very High Frequency Metal/Anomaly Detector}, volume={9454}, ISSN={["0277-786X"]}, DOI={10.1117/12.2182083}, abstractNote={In this paper the phase response and reflection coefficient notch of a metal/anomaly detector design that operates in the high to very high frequency range is studied. This design uses a high-Q tuned loop antenna for metal/anomaly detection. By measuring the reflection coefficient or voltage standing wave ratio a frequency notch can be detected. Tuning to the optimal location for detector performance can be accomplished by monitoring both the depth of the notch and the phase response. It has been experimentally observed that there are three regions of interest relative to the notch and phase response of the detector. One is at the frequency where the phase response is on a near vertical line of substantial phase shift and the notch is near its deepest depth. The second and third are at slightly higher and lower frequencies, where the slope of the phase shift line is reduced and the notch is still deep, but slightly removed from the frequency of maximum depth. As would be expected, initial experimentation indicates that the region of maximum detection performance, in terms of relative change in phase response, occurs when the phase response is at the center of the near vertical phase shift response near the location of the deepest notch. However, there may be advantages to the other two regions, since the response is more stable and less prone to false alarms. Performance results for various combinations of phase response and notch depth will be shown.}, journal={DETECTION AND SENSING OF MINES, EXPLOSIVE OBJECTS, AND OBSCURED TARGETS XX}, author={Heinz, Daniel C. and Brennan, Michael L. and Steer, Michael B. and Melber, Adam W. and Cua, John T.}, year={2015} }
@article{johnson_steer_2014, title={An Efficient Approach to Computing Third-Order Scattering of Sound by Sound With Application to Parametric Arrays}, volume={61}, ISSN={["1525-8955"]}, DOI={10.1109/tuffc.2012.005540}, abstractNote={A mathematical description of third-order scattered sound fields is derived using a multi-Gaussian beam (MGB) model that describes the sound field of any arbitrary axially symmetric beam as a series of Gaussian base functions. The third-order intermodulation (IM3) frequency components are produced by considering the cascaded nonlinear second-order effects when analyzing the interaction between the first-and second-order frequency components during the nonlinear scattering of sound by sound from two noncollinear ultrasonic baffled piston sources. The theory is extended to the modeling of the sound beams generated by parametric transducer arrays, showing that the MGB model can be efficiently used to calculate both the second- and third-order sound fields of the array. Measurements are presented for the IM3 frequency components and parametric array sound fields and comparisons of the model are made with traditional simulation results from direct numerical integration.}, number={10}, journal={IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL}, author={Johnson, Spencer J. and Steer, Michael B.}, year={2014}, month={Oct}, pages={1729–1741} }
@inproceedings{shityoy_schuchinsky_steer_wetherington_2014, title={Characterisation of nonlinear distortion and intermodulation in passive devices and antennas}, DOI={10.1109/eucap.2014.6902055}, abstractNote={The paper presents a conceptual discussion of the characterisation and phenomenology of passive intermodulation (PIM) by the localised and distributed nonlinearities in passive devices and antennas. The PIM distinctive nature and its impact on signal distortions are examined in comparison with similar effects in power amplifiers. The main features of PIM generation are discussed and illustrated by the example of PIM due to electro-thermal nonlinearity. The issues of measurement, discrimination and modelling of PIM generated by nonlinearities in passive RF components and antennas are addressed.}, booktitle={2014 8th european conference on antennas and propagation (eucap)}, author={Shityoy, A. and Schuchinsky, A. G. and Steer, M. B. and Wetherington, J. M.}, year={2014}, pages={1454–1458} }
@article{priyadarshi_davis_steer_franzon_2014, title={Thermal Pathfinding for 3-D ICs}, volume={4}, ISSN={["2156-3985"]}, DOI={10.1109/tcpmt.2014.2321005}, abstractNote={System architects traditionally use high-level models of component blocks to predict trends for various design metrics. However, with continually increasing design complexity and a confusing array of manufacturing choices, system-level design decisions cannot be made without considering physical-level details. This effect is more pronounced for 3-D integrated circuits (ICs) because it provides a plethora of physical-level design choices, such as the number of stacking layers and the type of 3-D bonding method, along with the choices provided by 2-D ICs. Thus, it is necessary for system-level flows to predict the complex interactions among system performance, power, temperature, floorplanning, process technology, computer architecture, and software/workloads. This is often called pathfinding. This paper presents a pathfinding flow that integrates SystemC transaction-level electrical and dynamic thermal simulations. The goal of this flow is to pass complex physical constraints to system architects in a convenient form. The applicability of the proposed flow is shown using an example stacking of two processor cores and L2 cache in two-tier 3-D stack.}, number={7}, journal={IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY}, author={Priyadarshi, Shivam and Davis, W. Rhett and Steer, Michael B. and Franzon, Paul D.}, year={2014}, month={Jul}, pages={1159–1168} }
@article{wyers_steer_kelley_franzon_2013, title={A Bounded and Discretized Nelder-Mead Algorithm Suitable for RFIC Calibration}, volume={60}, ISSN={["1558-0806"]}, DOI={10.1109/tcsi.2012.2230496}, abstractNote={This paper describes a calibration technique for noisy and nonconvex circuit responses based on the Nelder-Mead direct search algorithm. As Nelder-Mead is intended for unconstrained optimization problems, we present an implementation of the algorithm which is suitable for bounded and discretized RFIC calibration problems. We apply the proposed algorithm to the problem of spurious tone reduction via VCO control line ripple minimization for a PLL operating at a frequency of 12 GHz. For this nonconvex calibration test case, we show that a gradient descent-based algorithm has difficulty in reducing the VCO control line ripple, while the proposed algorithm reduces the relative power of the first harmonic reference spurs by at least 10 dBc and effectively enables design complexity reduction in the supporting analog calibration circuitry.}, number={7}, journal={IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS}, author={Wyers, Eric J. and Steer, Michael B. and Kelley, C. T. and Franzon, Paul D.}, year={2013}, month={Jul}, pages={1787–1799} }
@article{jang_kriplani_steer_2013, title={Behavioural modelling of amplifier asymmetry in the time domain}, volume={26}, ISSN={["1099-1204"]}, DOI={10.1002/jnm.1842}, abstractNote={SUMMARY
Power amplifier asymmetry is captured by a behavioural model that contains multiple slices representing the amplifier's nonlinearity and long-term, that is low frequency, memory. The simulation is performed entirely in the time domain, and the expense associated with performing a purely transient radio frequency (RF) simulation is circumvented by scaling down the carrier frequency by two orders of magnitude. This leads to a manageable transient simulation with results scaling back to the original carrier frequency. The model is empirical and can be easily implemented in any general purpose circuit simulation environment. The baseband portion of the model parameters was extracted and the simulation result was compared with measurement, thereby demonstrating that a nonlinear and accurate transient analysis routine can be effectively employed to capture memory-related RF power amplifier phenomena. Copyright © 2012 John Wiley & Sons, Ltd.}, number={2}, journal={INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS}, author={Jang, W. and Kriplani, N. M. and Steer, M. B.}, year={2013}, pages={112–126} }
@inproceedings{steer_wetherington_wilkerson_2013, title={Investigation of close-in passive intermodulation distortion on antennas}, DOI={10.1109/aps.2013.6711784}, abstractNote={Passive intermodulation distortion (PIM) generated on antennas is experimentally investigated and shown to agree with calculations based on an electro-thermal origin. Two-tone testing is used in the investigations with tone spacings ranging from 3 Hz to 100 kHz. The two-tone measurement system has a minimum spurious-free dynamic range of 125 dB at 3 Hz tone separation. Results show that at least some of the PIM generated by an antenna is due to electro-thermal effects but it is apparent that there are sources of PIM that cannot be described by electro-thermal effects alone.}, booktitle={2013 ieee antennas and propagation society international symposium (apsursi)}, author={Steer, M. B. and Wetherington, J. M. and Wilkerson, J. R.}, year={2013}, pages={2251–2252} }
@article{wetherington_steer_2013, title={Sensitive Vibration Detection Using Ground-Penetrating Radar}, volume={23}, ISSN={["1558-1764"]}, DOI={10.1109/lmwc.2013.2284779}, abstractNote={A high-dynamic-range vibration detection system is presented based on analog cancellation. The prototype system operates at 900 MHz and is shown to detect vibrational displacement as low as 11 nm for a rectangular aluminum plate at a standoff distance of 2 m. By operating at a lower frequency than previous radar vibrometers, the system gains ground-penetrating capability and is shown to detect vibrations through 13 cm of sand. A fundamental relationship is introduced relating the minimum detectable vibration displacement to the standoff distance and system dynamic range.}, number={12}, journal={IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS}, author={Wetherington, Joshua M. and Steer, Michael B.}, year={2013}, month={Dec}, pages={680–682} }
@article{zhu_yelten_steer_franzon_2013, title={Variation-Aware Circuit Macromodeling and Design Based on Surrogate Models}, volume={197}, ISBN={["978-3-642-34335-3"]}, ISSN={["2194-5365"]}, DOI={10.1007/978-3-642-34336-0_17}, journal={SIMULATION AND MODELING METHODOLOGIES, TECHNOLOGIES AND APPLICATIONS}, author={Zhu, Ting and Yelten, Mustafa Berke and Steer, Michael B. and Franzon, Paul D.}, year={2013}, pages={255–269} }
@article{ding_gard_steer_2012, title={A Highly Linear and Efficient CMOS RF Power Amplifier With a 2-D Circuit Synthesis Technique}, volume={60}, ISSN={["1557-9670"]}, DOI={10.1109/tmtt.2012.2206824}, abstractNote={A 2-D circuit synthesis technique (2DCST) is introduced that simultaneously linearizes the AM–AM and AM–PM distortions of CMOS RF power amplifiers (PAs). A class-AB nMOS RF PA fabricated in a ${0.18-}\mu{\hbox {m}}$ CMOS process is reported. With a WCDMA signal, the amplifier achieved 41.6% power-added efficiency (PAE) with $-{\hbox{33-dBc}}$ single-adjacent channel power ratio (ACPR1) and 38.5% PAE with $-{\hbox{40-dBc}}$ ACPR1 at output powers of 24.9 and 24.0 dBm, respectively. This state-of-the-art linearity and efficiency performance is comparable to that of GaAs HBT linear RF PAs. The 2DCST is applicable to a broad range of analog circuits and other semiconductor technologies.}, number={9}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Ding, Miaofu and Gard, Kevin G. and Steer, Michael B.}, year={2012}, month={Sep}, pages={2851–2862} }
@article{harris_priyadarshi_melamed_ortega_manohar_dooley_kriplani_davis_franzon_steer_et al._2012, title={A Transient Electrothermal Analysis of Three-Dimensional Integrated Circuits}, volume={2}, ISSN={["2156-3985"]}, DOI={10.1109/tcpmt.2011.2178414}, abstractNote={A transient electrothermal simulation of a 3-D integrated circuit (3DIC) is reported that uses dynamic modeling of the thermal network and hierarchical electrothermal simulation. This is a practical alternative to full transistor electrothermal simulations that are computationally prohibitive. Simulations are compared to measurements for a token-generating asynchronous 3DIC clocking at a maximum frequency of 1 GHz. The electrical network is based on computationally efficient electrothermal macromodels of standard and custom cells. These are linked in a physically consistent manner with a detailed thermal network extracted from an OpenAccess layout file. Coupled with model-order reduction techniques, hierarchical dynamic electrothermal simulation of large 3DICs is shown to be tractable, yielding spatial and temporal selected transistor-level thermal profiles.}, number={4}, journal={IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY}, author={Harris, T.R. and Priyadarshi, S. and Melamed, S. and Ortega, C. and Manohar, R. and Dooley, S.R. and Kriplani, N.M. and Davis, W.R. and Franzon, Paul and Steer, M.B. and et al.}, year={2012}, month={Apr}, pages={660–667} }
@article{garner_steer_2012, title={A cascaded second-order approach to computing third-order scattering of noncollinear acoustic beams}, volume={73}, ISSN={["1872-910X"]}, DOI={10.1016/j.apacoust.2011.12.013}, abstractNote={A theoretical development of the third-order nonlinear scattering of sound from two noncollinear ultrasonic beams produced by baffled piston sources is presented. The third-order intermodulation (IM3) frequency components are derived by exploiting cascaded second-order nonlinear effects where the quadratic nonlinear interaction of second-order frequency components with first-order (primary) frequency components is considered. It is shown that cascaded second-order interactions generate intermodulation frequency components that are equivalent to those generated by cubic nonlinear effects. Comparison of measured and modeled amplitude sweeps demonstrate the three-to-one gain in decibels of the amplitudes of the third-order intermodulation frequency components to that of the primary frequency components. Measurements are also presented for the farfield interaction of distantly spaced sources, which results in a highly focused ultrasonic parametric array. Also considered are the nearfield interaction of closely spaced sources, which results in scattering, with good agreement to the theory.}, number={12}, journal={APPLIED ACOUSTICS}, author={Garner, Glenwood and Steer, Michael B.}, year={2012}, month={Dec}, pages={1220–1230} }
@article{yelten_franzon_steer_2012, title={Analog Negative-Bias-Temperature-Instability Monitoring Circuit}, volume={12}, ISSN={["1558-2574"]}, DOI={10.1109/tdmr.2011.2178096}, abstractNote={A negative-bias-temperature-instability (NBTI) monitor subcircuit is presented and implemented in 65-nm CMOS technology. The subcircuit can be incorporated in various analog circuit blocks subject to different variability, stress, and aging histories. For an amplifier block, the NBTI monitor is a linear sensor, and sensing is provided as variation of the amplifier gain in response to NBTI-induced bias variation. The monitor sensitivity in this configuration is 3.15 V-1 and is demonstrated through electrothermal stress on the amplifier circuit.}, number={1}, journal={IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY}, author={Yelten, Mustafa Berke and Franzon, Paul D. and Steer, Michael B.}, year={2012}, month={Mar}, pages={177–179} }
@inproceedings{wetherington_steer_2012, title={Characterization of the dynamic range of a single aperture communications system}, DOI={10.1109/inmmic.2012.6331945}, abstractNote={A resonant antenna displays passive intermodulation related to antenna vibrations at levels that impact communications systems. A non-resonant antenna was immune to structure vibrations. Both antennas were of solid construction with thick metalization and did not exhibit electro-thermal passive intermodulation distortion previously observed with microstrip structures. The ultimate dynamic ranges of two antennas are explored using a measurement system with a dynamic range of 98 dB at one hertz offset from a 30 dBm, 500 MHz transmit signal. This increased to 140 dB when the separation increased to 100 Hz.}, booktitle={2012 Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits (INMMIC)}, author={Wetherington, J. M. and Steer, M. B.}, year={2012} }
@article{yelten_franzon_steer_2012, title={Comparison of modeling techniques in circuit variability analysis}, volume={25}, ISSN={["1099-1204"]}, DOI={10.1002/jnm.836}, abstractNote={Three nonlinear reduced-order modeling approaches are compared in a case study of circuit variability analysis for deep submicron complementary metal-oxide-semiconductor technologies where variability of the electrical characteristics of a transistor can be significantly detrimental to circuit performance. The drain currents of 65 nm N-type metal-oxide-semiconductor and P-type metal-oxide-semiconductor transistors are modeled in terms of a few process parameters, terminal voltages, and temperature using Kriging-based surrogate models, neural network-based models, and support vector machine-based models. The models are analyzed with respect to their accuracy, establishment time, size, and evaluation time. It is shown that Kriging-based surrogate models and neural network-based models can be generated with sufficient accuracy that they can be used in circuit variability analysis. Numerical experiments demonstrate that for smaller circuits, Kriging-based surrogate modeling yields results faster than the neural network-based models for the same accuracy whereas for larger circuits, neural network-based models are preferred as, in all metrics, better performance is obtained. Within-die variations for an XOR circuit are analyzed, and it is shown that the nonlinear reduced-order models developed can more effectively capture the within-die variations than the traditional process corner analysis. Copyright © 2011 John Wiley & Sons, Ltd.}, number={3}, journal={INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS}, author={Yelten, Mustafa Berke and Franzon, Paul D. and Steer, Michael B.}, year={2012}, pages={288–302} }
@article{priyadarshi_harris_melamed_otero_kriplani_christoffersen_manohar_dooley_davis_franzon_et al._2012, title={Dynamic electrothermal simulation of three-dimensional integrated circuits using standard cell macromodels}, volume={6}, ISSN={1751-858X}, url={http://dx.doi.org/10.1049/iet-cds.2011.0061}, DOI={10.1049/iet-cds.2011.0061}, abstractNote={Physics-based compact electrothermal macromodels of standard cells are developed for fast dynamic simulation of three-dimensional integrated circuits (3DICs). Such circuits can have high thermal densities and thermal effects often limit their performance. The macromodels developed here use fewer state-variables than a discrete transistor-level implementation while retaining transistor-level accuracy. This results in significant speed-up over transistor-level simulation for large-scale circuits. The macromodel-based methodology enables robust and significantly faster dynamic electrothermal simulation over the long times required for thermal transients to subside. Consequently, transient junction temperature can be examined in the design phase. Simulated junction and measured surface thermal transients are compared.}, number={1}, journal={IET Circuits, Devices & Systems}, publisher={Institution of Engineering and Technology (IET)}, author={Priyadarshi, S. and Harris, T.R. and Melamed, S. and Otero, C. and Kriplani, N.M. and Christoffersen, C.E. and Manohar, R. and Dooley, S.R. and Davis, W.R. and Franzon, P.D. and et al.}, year={2012}, pages={35} }
@article{feng_lueck_temple_steer_2012, title={High-Performance Solenoidal RF Transformers on High-Resistivity Silicon Substrates for 3D Integrated Circuits}, volume={60}, ISSN={["1557-9670"]}, DOI={10.1109/tmtt.2012.2195026}, abstractNote={Soleniod-like transformers based on a traveling-wave design and using advanced through silicon via process technology are reported for operation at frequencies from 1 to 14 GHz. The symmetrical 1:1 transformers are designed as compact slow-wave transmission-line structures with well-defined signal return paths. One-, two-, three-, and four-turn transformers have 1-dB bandwidths ranging from 6 to 9.2 GHz, and midband insertion losses from 0.24 to 0.37 dB. The measured intrinsic loss is 0.46 dB or less up to 10 GHz, and 0.97 dB up to 14 GHz. Relatively simple and scalable physically based lumped-element circuit models accurately predict the performance of these low parasitic transformers.}, number={7}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Feng, Zhiping and Lueck, Matthew R. and Temple, Dorota S. and Steer, Michael B.}, year={2012}, month={Jul}, pages={2066–2072} }
@article{melamed_thorolfsson_harris_priyadarshi_franzon_steer_davis_2012, title={Junction-level thermal analysis of 3-D integrated circuits using high definition power blurring}, volume={31}, DOI={10.1109/tcad.2011.2180384}, abstractNote={The degraded thermal path of 3-D integrated circuits (3DICs) makes thermal analysis at the chip-scale an essential part of the design process. Performing an appropriate thermal analysis on such circuits requires a model with junction-level fidelity; however, the computational burden imposed by such a model is tremendous. In this paper, we present enhancements to two thermal modeling techniques for integrated circuits to make them applicable to 3DICs. First, we present a resistive mesh-based approach that improves on the fidelity of prior approaches by constructing a thermal model of the full structure of 3DICs, including the interconnect. Second, we introduce a method for dividing the thermal response caused by a heat load into a high fidelity “near response” and a lower fidelity “far response” in order to implement Power Blurring high definition (HD), a hierarchical thermal simulation approach based on Power Blurring that incorporates the resistive mesh-based models and allows for junction-level accuracy at the full-chip scale. The Power Blurring HD technique yields approximately three orders of magnitude of improvement in memory usage and up to six orders of magnitude of improvement in runtime for a three-tier synthetic aperture radar circuit, as compared to using a full-chip junction-scale resistive mesh-based model. Finally, measurement results are presented showing that Power Blurring high definition (HD) accurately determines the shape of the thermal profile of the 3DIC surface after a correction factor is added to adjust for a discrepancy in the absolute temperature values.}, number={5}, journal={IEEE Transactions on Computer-aided Design of Integrated Circuits and Systems}, author={Melamed, S. and Thorolfsson, T. and Harris, T. R. and Priyadarshi, S. and Franzon, Paul and Steer, M. B. and Davis, W. R.}, year={2012}, pages={676–689} }
@article{priyadarshi_saunders_kriplani_demircioglu_davis_franzon_steer_2012, title={Parallel Transient Simulation of Multiphysics Circuits Using Delay-Based Partitioning}, volume={31}, ISSN={["1937-4151"]}, DOI={10.1109/tcad.2012.2201156}, abstractNote={A parallel transient simulation technique for multiphysics circuits is presented. The technique develops partitions utilizing the inherent delay present within a circuit and between physical domains. A state-variable-based circuit delay element is presented, which implements the coupling between two spatially or temporally isolated circuit partitions. A parallel delay-based iterative approach for interfacing delay-partitioned subcircuits is applied, which achieves the reasonable accuracy of nonparallel circuit simulation if both incorporate the same interblock delay. The partitioned subcircuits are distributed to different cores of a shared-memory multicore processor and solved in parallel. A multithreaded implementation of the methodology using OpenMP is presented. Examples showing superlinear speedup compared to unpartitioned single-core simulation using the direct method are presented. This paper also discusses the impact of load balancing and absolute delay on simulation speedup.}, number={10}, journal={IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS}, author={Priyadarshi, Shivam and Saunders, Christopher S. and Kriplani, Nikhil M. and Demircioglu, Harun and Davis, W. Rhett and Franzon, Paul D. and Steer, Michael B.}, year={2012}, month={Oct}, pages={1522–1535} }
@article{saunders_steer_2012, title={Passivity Enforcement for Admittance Models of Distributed Networks Using an Inverse Eigenvalue Method}, volume={60}, ISSN={["0018-9480"]}, DOI={10.1109/tmtt.2011.2171500}, abstractNote={Most transient circuit simulators are based on admittance representations of the constituent circuit elements. It is therefore natural to use admittance parameter descriptions of linear networks, preferably in the form of rational transfer functions that can be directly implemented in the analysis. A problem arises when the measured or calculated frequency-domain response of a linear distributed network must be derived from data that has inherent error, is of limited bandwidth, or is not in the appropriate rational form. A reduced-order rational model that is causal, stable, and passive must be developed. Previous methods of deriving rational functions for the admittance parameters of a network do guarantee stability and causality, but passivity of the model must be assured through subsequent post-processing. Enforcing passivity requires modification of the state-space parameters of the model with consequent introduction of errors. This paper reports on a procedure to simultaneously achieve passivity, accuracy, causality, and stability in the development of an admittance macromodel described using a matrix of rational functions. An iterative inverse eigenvalue algorithm enforces passivity, and is applied by conjoining sets of eigenvalue and admittance constraints. These constraints form a monolithic projection matrix, which simultaneously addresses both passivity and accuracy of the model.}, number={1}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Saunders, Christopher S. and Steer, Michael B.}, year={2012}, month={Jan}, pages={8–20} }
@inproceedings{yelten_franzon_steer_2012, title={Process mismatch analysis based on reduced-order models}, DOI={10.1109/isqed.2012.6187561}, abstractNote={This paper describes a methodology based on reduced-order models to investigate the effects of process mismatch in analog circuits in the presence of reliability degradation. Neural network-based reduced-order models for the DC drain current, I _{ds} , of 65 nm n- and p-channel transistors have been generated in terms of six process parameters, temperature, and device age. The models identify the contribution of process parameters to the mismatch of n- and p-channel transistors as they age. Hot carrier injection (HCI) is considered as the main reliability degradation for n-channel devices and negative bias temperature instability (NBTI) is considered for p-channel devices. It is demonstrated that the variations of the effective channel length and intrinsic threshold voltage are major contributors to device mismatch in the absence of aging. Finally, a beta multiplier current reference is analyzed using the developed models for the impact of process mismatch with and without the aging effects. It is shown that in a cascode current mirror the variability of the reference current can be reduced by ensuring that the same rail transistors experience similar variations.}, booktitle={2012 13th international symposium on quality electronic design (isqed)}, author={Yelten, M. B. and Franzon, Paul and Steer, M. B.}, year={2012}, pages={648–655} }
@article{wetherington_steer_2012, title={Robust Analog Canceller for High-Dynamic-Range Radio Frequency Measurement}, volume={60}, ISSN={["0018-9480"]}, DOI={10.1109/tmtt.2012.2189230}, abstractNote={An automated analog canceller is presented that uses feedforward cancellation in a bridge configuration. A minimum of 70 dB of analog cancellation is obtained. The canceller is used to construct an intermodulation distortion measurement system achieving up to 120 dBc of intermodulation dynamic range in two-port transmission testing and 140 dBc of intermodulation dynamic range in one-port reflection testing for frequency separations of at least 1 kHz. At a two-tone frequency separation of 1 Hz, the respective dynamic ranges are at least 94 and 111 dBc. The relationship of cancellation performance and dynamic range is examined in terms of application-specific definitions of dynamic range. The system is then used to measure passive intermodulation distortion using a two-tone test with a tone frequency separation from 1 Hz to 100 MHz.}, number={6}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Wetherington, Joshua M. and Steer, Michael B.}, year={2012}, month={Jun}, pages={1709–1719} }
@article{lam_haridasan_feng_steer_kingon_maria_2012, title={Scaling Issues in Ferroelectric Barium Strontium Titanate Tunable Planar Capacitors}, volume={59}, ISSN={["1525-8955"]}, DOI={10.1109/tuffc.2012.2179}, abstractNote={We report on the geometric limits associated with tunability of interdigitated capacitors, specifically regarding the impact of a parasitic non-tunable component that necessarily accompanies a ferroelectric surface capacitor, and can dominate the voltage-dependent response as capacitor dimensions are reduced to achieve the small capacitance values required for impedance matching in the X band. We present a case study of simple gap capacitors prepared and characterized as a function of gap width (i.e., the distance between electrodes) and gap length (i.e., the edge-to-edge gap distance). Our series of measurements reveals that for gap widths in the micrometer range, as gap lengths are reduced to meet sub-picofarad capacitance values, the non-tunable parasitic elements limit the effective tunability. These experimental measurements are supported by a companion set of microwave models that clarify the existence of parallel parasitic elements.}, number={2}, journal={IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL}, author={Lam, Peter G. and Haridasan, Vrinda and Feng, Zhiping and Steer, Michael B. and Kingon, Angus I. and Maria, Jon-Paul}, year={2012}, month={Feb}, pages={198–204} }
@article{wetherington_steer_2012, title={Standoff Acoustic Modulation of Radio Frequency Signals in a Log-Periodic Dipole Array Antenna}, volume={11}, ISSN={["1536-1225"]}, DOI={10.1109/lawp.2012.2210692}, abstractNote={An acoustic tone isonifying an antenna is shown to produce radio frequency (RF) distortion in a log-periodic dipole array. This distortion is capable of interfering with a sensitive receiver. The passive distortion produces two sidebands, the powers of which have a 1:1 relationship with both the RF and acoustic tone, but have nonmonotonic behavior with respect to RF and acoustic frequency.}, journal={IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS}, author={Wetherington, Joshua M. and Steer, Michael B.}, year={2012}, pages={885–888} }
@article{zhu_steer_franzon_2012, title={Surrogate Model-Based Self-Calibrated Design for Process and Temperature Compensation in Analog/RF Circuits}, volume={29}, ISSN={0740-7475}, DOI={10.1109/mdt.2012.2220332}, abstractNote={Analog circuits designed in submicrometer nodes suffer from process variations, typically requiring calibration in order to center their performance parameters and to recover yield loss. This article presents a design flow to find appropriate tuning knob settings to compensate for different process variation scenarios.}, number={6}, journal={IEEE Design Test of Computers}, author={Zhu, T. and Steer, M. B. and Franzon, P. D.}, year={2012}, month={Dec}, pages={74–83} }
@article{garner_steer_2012, title={Third-Order Parametric Array Generated by Distantly Spaced Primary Ultrasonic Tones}, volume={59}, ISSN={["1525-8955"]}, DOI={10.1109/tuffc.2012.2255}, abstractNote={Traditional parametric arrays are produced by a second-order nonlinear interaction between two primary ultrasonic tones that are close in frequency, resulting in a difference tone that is in the audio band. This article presents a parametric array produced by a third-order nonlinear interaction between two primary ultrasonic tones that are distantly spaced in frequency such that one tone is approximately the second harmonic of the other. The result is a third-order lower intermodulation (IM3) tone in the audio band with greater directivity and lower side lobe amplitude than comparable second-order fields. Measurements are presented that compare the directivity of 1-, 2-, and 4-kHz difference tones to that of 1-, 2-, and 4-kHz IM3 lower tones. Furthermore, a cascaded second-order approach for N-element transducer arrays is used to model third-order scattering with good agreement between measurement and theory.}, number={4}, journal={IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL}, author={Garner, Glenwood and Steer, Michael B.}, year={2012}, month={Apr}, pages={776–784} }
@inproceedings{steer_wilkerson_kriplani_wetherington_2012, title={Why it is so hard to find small radio frequency signals in the presence of large signals}, DOI={10.1109/inmmic.2012.6331916}, abstractNote={The essence of radar, radio and wireless sensor engineering is extracting small information-bearing signals. This is notoriously difficult and engineers compensate by transmitting high power signals, reducing range, and spacing wireless systems in frequency and time. New understandings of passive intermodulation distortion, thermal effects, time-frequency effects, and noise are presented. It is seen that the familiar frequency-domain-based abstractions have missed important underlying physics. Through greater understanding, RF engineers can develop microwave systems with far lower levels of distortion and noise.}, booktitle={2012 Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits (INMMIC)}, author={Steer, M. B. and Wilkerson, J. R. and Kriplani, N. M. and Wetherington, J. M.}, year={2012} }
@article{zhu_steer_franzon_2011, title={Accurate and Scalable IO Buffer Macromodel Based on Surrogate Modeling}, volume={1}, ISSN={["2156-3985"]}, DOI={10.1109/tcpmt.2011.2138704}, abstractNote={In this paper, a new method is proposed to generate accurate and scalable macromodels for input/output buffers. The method characterizes the physically based model elements with adaptive multivariate surrogate modeling techniques in order to achieve high fidelity and process-voltage-temperature scalability. Both single-ended and differential output buffer circuit examples demonstrate that the proposed modeling method offers good accuracy and flexible scalability to facilitate signal integrity analysis.}, number={8}, journal={IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY}, author={Zhu, Ting and Steer, Michael B. and Franzon, Paul D.}, year={2011}, month={Aug}, pages={1240–1249} }
@article{hu_gard_steer_2011, title={Calibrated non-linear vector network measurement without using a multi-harmonic generator}, volume={5}, ISSN={["1751-8725"]}, DOI={10.1049/iet-map.2010.0580}, abstractNote={The current generation of non-linear vector network analysers (NVNA) relies on a multi-harmonic generator to establish an absolute phase reference. Such a reference may not be readily available or, more importantly, may impose limitations on tone spacing in multi-tone testing for one type of NVNA based on a four-port VNA. The latter is a severe limitation when characterising memory behaviour in RF non-linear circuits. Here a hybrid NVNA is proposed that combines a sampling oscilloscope, a four-port VNA and phase-locked signal generators. A signal generator, phase locked to generators that are combined as the multi-tone excitation, provides the relative phase reference during swept power measurements using the VNA. The high dynamic range VNA-based measurements are corrected in absolute phase using the oscilloscope-based NVNA measurement at a specific power level. The hybrid NVNA has high dynamic range and the lower bound on tone spacing is determined by the memory depth of the oscilloscope, the windowing effect of the VNA receivers and the phase noise of the multi-tone sources. At 2 GHz, the hybrid NVNA has a dynamic range of 40 dB at 200 Hz tone spacing for a two-tone signal, increasing to more than 80 dB for tone spacings of 200 kHz and greater.}, number={5}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Hu, J. and Gard, K. G. and Steer, M. B.}, year={2011}, month={Apr}, pages={616–624} }
@article{wilkerson_lam_gard_steer_2011, title={Distributed Passive Intermodulation Distortion on Transmission Lines}, volume={59}, ISSN={["1557-9670"]}, DOI={10.1109/tmtt.2011.2106138}, abstractNote={A theoretical treatment of distributed electro-thermally induced intermodulation distortion is developed for microstrip transmission lines. The growth of passive intermodulation distortion (PIM) along the length of a line is derived accounting for both loss and electrical dispersion. PIM dependencies on width, length, thickness, and substrate parameters are analyzed leading to design guidelines for low distortion lines. Single metal silver transmission lines are fabricated on sapphire and fused-quartz substrates to isolate the electro-thermal effect and validate the model. Electro-thermal PIM is measured in a two-tone test with tone separation ranging from 4 Hz to 10 kHz.}, number={5}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Wilkerson, Jonathan R. and Lam, Peter G. and Gard, Kevin G. and Steer, Michael B.}, year={2011}, month={May}, pages={1190–1205} }
@article{hu_lowry_gard_steer_2011, title={Non-linear radio frequency model identification using a hybrid genetic optimiser for minimal user intervention}, volume={5}, ISSN={["1751-8733"]}, DOI={10.1049/iet-map.2010.0435}, abstractNote={An adaptive reduced-order procedure for developing grey-box models of radio frequency systems is presented. The stochastic model extraction combines a modified genetic algorithm and the Nelder–Mead simplex algorithm to present a user with a range of possible good models from which the user can use intuition to select the most physically realistic candidate. The procedure is ideal for identifying models given incomplete observations, noisy data and inexact model structure. This procedure replaces the commonly used human-in-the-loop ad hoc deterministic approach in which a skilled operator must guide model fitting. Being able to use an expanded range of model architectures beyond the Wiener and Hammerstein family, the stochastic approach, utilisation of incomplete observations and extraction of multiple distinct model candidates, enables the insight and intuition of a skilled operator to be used to advantage. The extraction of a multistage microwave amplifier exhibiting long-term memory effects is used as an example.}, number={15}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Hu, J. and Lowry, J. Q. and Gard, K. G. and Steer, M. B.}, year={2011}, month={Dec}, pages={1880–1890} }
@article{haridasan_lam_feng_fathelbab_maria_kingon_steer_2011, title={Tunable ferroelectric microwave bandpass filters optimised for system-level integration}, volume={5}, ISSN={["1751-8733"]}, DOI={10.1049/iet-map.2010.0461}, abstractNote={Tunable bandpass filters are critical components in emerging radio frequency front-ends. A system-aware design guideline and figure of merit (FOM) are developed for optimum system-level performance. The optimisation metric discussed here deviates from earlier guidelines as the filter bandwidth is allowed to vary in the tunable range, constrained only by the downstream system analogue to digital converter. The system-aware FOM uses worst-case filter design parameters and a tuning sensitivity term that captures the frequency tunability relative to material tunability. A 6.74–8.23 GHz tunable barium strontium titanate-based filter is presented as an example to illustrate the design methodology.}, number={10}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Haridasan, V. and Lam, P. G. and Feng, Z. and Fathelbab, W. M. and Maria, J-P. and Kingon, A. I. and Steer, M. B.}, year={2011}, month={Jul}, pages={1234–1241} }
@article{kosinski_palmer_steer_2011, title={Unified Understanding of RF Remote Probing}, volume={11}, ISSN={["1558-1748"]}, DOI={10.1109/jsen.2011.2167228}, abstractNote={Recent research has examined several novel radio frequency (RF) remote probing techniques. These new results are joined with the prior art leading to a unified understanding of RF remote probing that articulates the fundamental principles involved and allows extension to the analysis of additional “new” RF probing techniques. Two significant aspects in RF probing are emphasized: 1) information, coding, and signal theory considerations are identified as these establish bounds on probe performance against a specific information task and 2) building upon the well-known radar equation, the object cross section is generalized to be an interaction term describing a much broader range of interactions than simply reflection. These results are significant in enabling the rapid analysis and evaluation of “new” RF sensing techniques proposed to accomplish a variety of functions in the detection and identification of both natural and manmade objects.}, number={12}, journal={IEEE SENSORS JOURNAL}, author={Kosinski, John A. and Palmer, W. Devereux and Steer, Michael B.}, year={2011}, month={Dec}, pages={3055–3063} }
@article{wilkerson_gard_steer_2010, title={Automated Broadband High-Dynamic-Range Nonlinear Distortion Measurement System}, volume={58}, ISSN={["1557-9670"]}, DOI={10.1109/tmtt.2010.2045525}, abstractNote={This paper presents an intermodulation distortion measurement system based on automated feedforward cancellation that achieves 113 dB of broadband spurious-free dynamic range for discrete tone separations down to 100 Hz. For 1-Hz tone separation, the dynamic range is 106 dB, limited by carrier phase noise. A single-tone cancellation formula is developed requiring only the power of the probing signal and the power of the combined probe and cancellation signal so that the phase shift required for cancellation can be predicted. The technique is applied to a two-path feedforward cancellation system in a bridge configuration. The effects of reflected signals and of group delay on system performance is discussed. Spurious frequency content and interchannel coupling are analyzed with respect to system linearity. Feedforward cancellation and consideration of electromagnetic radiation coupling and reverse-wave isolation effects extends the dynamic range of spectrum and vector analyzers by at least 40 dB. Application of the technique to the measurement of correlated and uncorrelated nonlinear distortion of an amplified wideband code-division multiple-access signal is presented.}, number={5}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Wilkerson, Jonathan R. and Gard, Kevin G. and Steer, Michael B.}, year={2010}, month={May}, pages={1273–1282} }
@article{li_hoover_gard_steer_2010, title={Behavioural modelling and impact analysis of physical impairments in quadrature modulators}, volume={4}, ISSN={["1751-8733"]}, DOI={10.1049/iet-map.2009.0278}, abstractNote={Non-linear distortion and linear static errors (DC offset and gain/phase imbalance) are the major analogue impairments in microwave I/Q quadrature modulators. They can adversely impact the performance of the systems using them, especially for direct-conversion transceiver systems. The impacts of these impairments were investigated for three different modulator applications: double sideband modulation, zero intermediate frequency (IF) single sideband (SSB) orthogonal frequency-division multiplexing (OFDM) modulation and low-IF SSB OFDM modulation. A behavioural model for characterising the non-linear response and the linear static errors was developed. The non-linear characteristic of each input was modelled by a complex power series based on amplitude-to-amplitude modulation and amplitude-to-phase modulation measurements. The linear static errors were modelled as three static error terms added into the complex power series based on a four-DC-point vector network analyser measurement. The non-linear model was validated by measurements with three types of signals representing the three modulator applications.}, number={12}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Li, M. and Hoover, L. and Gard, K. G. and Steer, M. B.}, year={2010}, month={Dec}, pages={2144–2154} }
@article{mazzaro_steer_gard_2010, title={Intermodulation distortion in narrowband amplifier circuits}, volume={4}, ISSN={["1751-8733"]}, DOI={10.1049/iet-map.2009.0281}, abstractNote={The contribution of bandpass filter memory to intermodulation distortion in narrowband amplifier circuits is examined. A method for generating multisines from filtered switched tones is presented, and techniques for measuring an amplifier's IP3 and extracting a filter's passband using these multisines are developed. It is shown that amplified filtered pulses produce intermodulation distortion in frequency-hopping communication systems. In the experimental study, 465 and 900-MHz Chebyshev bandpass filters are considered.}, number={9}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Mazzaro, G. J. and Steer, M. B. and Gard, K. G.}, year={2010}, month={Sep}, pages={1149–1156} }
@article{mazzaro_gard_steer_2010, title={Linear amplification by time-multiplexed spectrum}, volume={4}, ISSN={["1751-858X"]}, DOI={10.1049/iet-cds.2009.0263}, abstractNote={A new waveform processing technique for reducing intermodulation distortion (IMD) generated by an amplitude-modulated signal is presented. The technique eliminates amplifier-generated IMD by time-multiplexing portions of the signal spectrum prior to amplification. The input signal is described as a sum of sinusoidal signals. The peak-to-average ratio of the time-multiplexed amplifier input is lower than that of its non-multiplexed counterpart, but it contains spectral aliases at multiples of the switching frequency. Thus, the reduction in distortion of the desired amplified signal is achieved at the expense of momentarily widening the signal bandwidth. Following amplification, the desired signal is recovered using a bandpass filter which spreads the signal in time and narrows its bandwidth. An analytical expression for distortion reduction when amplifying two multiplexed carriers is developed along with measurements verifying the theory. Distortion reduction is demonstrated experimentally at 3.6 GHz for 2–20 multiplexed carriers, and linear recovery is demonstrated for four multiplexed carriers. The technique reduces third-order IMD by 8–22 dB in experimental measurements of three different amplifiers. The presented technique has the unique property of improving linearity without requiring feedback, feedforward cancellation or calibration.}, number={5}, journal={IET CIRCUITS DEVICES & SYSTEMS}, author={Mazzaro, G. J. and Gard, K. G. and Steer, M. B.}, year={2010}, month={Sep}, pages={392–402} }
@article{saunders_mazzaro_steer_2010, title={Robust reduced-order modelling of distributed linear networks}, volume={4}, ISSN={["1751-8733"]}, DOI={10.1049/iet-map.2009.0554}, abstractNote={Foster's canonical form provides a causal bridge between the transfer function representation of the characteristics of a distributed structure and both time-domain and frequency-domain non-linear circuit simulation. It is particularly advantageous in modelling bandpass-like characteristics. In the modelling procedure, a transfer function having Foster's canonical form is fitted to measured or simulated data which may not have an inherent pole-zero description. Even if there is a good transfer function representation, the number of poles required for a reasonable fit is not known a priori which can lead to poor models that may cause convergence problems during either fitting or simulation. In this study, an extension of Foster's model is developed and a robust procedure for fitting the transfer function to data without a priori knowledge of the number of poles is presented. A robust stamp for implementation of the model in a transient circuit simulator is developed.}, number={7}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Saunders, C. S. and Mazzaro, G. J. and Steer, M. B.}, year={2010}, month={Jul}, pages={962–973} }
@inproceedings{harris_melamed_luniya_davis_steer_doxsee_obermiller_hawkinson_2010, title={Thermal analysis and verification of a mounted monolithic integrated circuit}, ISSN={["1558-058X"]}, DOI={10.1109/secon.2010.5453924}, abstractNote={As circuit density increases and high-power applications are facilitated, thermal considerations become paramount a design concern. In this paper, a high power monolithic microwave integrated circuit (MMIC) is modeled by the fREEDA multi-physics simulator and measured for validation. While validation is the crux of any simulation model, it is known that thermal measurements accurate to a high resolution are problematic. As such, the thermal profile of integrated circuits cannot be measured directly with infrared thermal imaging due to unequivalent emissivities of materials. It becomes necessary to use an absorptive ink to approximate a blackbody so that the infrared emissions can be used to infer temperature. The impact and effect of this thermal imaging technique is investigated in this work by comparing measurements with detailed thermal simulations with and without the surface treatment. Thermal analysis uses the finite element method and a reduced-order model based on cuboids with effective thermal conductivities. The end goal is to provide a simulation tool to designers, which can be extended to any project which requires attention to thermal preference.}, booktitle={Proceedings of the IEEE SoutheastCon 2010 (SoutheastCon)}, author={Harris, T.R. and Melamed, S. and Luniya, S. and Davis, W.R. and Steer, M.B. and Doxsee, L.E. and Obermiller, K. and Hawkinson, C.}, year={2010}, pages={37–40} }
@article{mazzaro_steer_gard_2009, title={Filter characterisation using one-port pulsed radio-frequency measurements}, volume={3}, ISSN={["1751-8733"]}, DOI={10.1049/iet-map:20080111}, abstractNote={A method for extracting the loaded quality factor of the first resonator of a bandpass filter using one-port measurements is introduced. Properties of the quality factor are reviewed, and a time-domain approximation is used to estimate the loaded Q value from the decay rate of the filter's natural response. Narrowband 900 MHz Chebyshev filters are characterised.}, number={2}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Mazzaro, G. J. and Steer, M. B. and Gard, K. G.}, year={2009}, month={Mar}, pages={303–309} }
@article{kriplani_fletcher_langdon_penney_fast_steer_2009, title={Integration of FDTD EM Analysis and Transient Circuit Simulation of RF Systems}, ISBN={["978-1-4244-2803-8"]}, ISSN={["2576-7216"]}, DOI={10.1109/mwsym.2009.5166012}, abstractNote={A combined transient simulation of a 300 MHz input, 20 MHz output RF radio transceiver system was performed using an industry standard FDTD simulator integrated with an open source state-variable based multi-physics simulator. The two simulators were interfaced at every time step and several nonlinear iterations were performed at each step in order to ensure simulation convergence of the system which contains strong nonlinearities and a wide range of signal strengths at different points in the system.}, journal={2009 IEEE/MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM, VOLS 1-3}, author={Kriplani, Nikhil M. and Fletcher, Jonathan and Langdon, Scott and Penney, Christopher W. and Fast, Stephen A. and Steer, Michael B.}, year={2009}, pages={1577-+} }
@article{mazzaro_gard_steer_2009, title={Low Distortion Amplification of Multisine Signals Using a Time-Frequency Technique}, ISBN={["978-1-4244-2803-8"]}, ISSN={["0149-645X"]}, DOI={10.1109/mwsym.2009.5165843}, abstractNote={A novel time-frequency technique is presented for reducing intermodulation distortion when a multisine signal is applied to a nonlinear radio-frequency amplifier. A fast periodic switch is used to apply only one spectral tone at a time to the nonlinear amplifier. A bandpass filter following the amplifier removes switching spurious signals, leaving only the linearly amplified multisine signal at the output. The technique is used to linearize the response of a broadband amplifier with a four-tone uniform phase input signal centered at 465 MHz. The technique yields a 14 dB improvement in intermodulation distortion in comparison to the response of the original four-tone signal at the same output power.}, journal={2009 IEEE/MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM, VOLS 1-3}, author={Mazzaro, Gregory J. and Gard, Kevin G. and Steer, Michael B.}, year={2009}, pages={901–904} }
@article{feng_fathelbab_lam_haridasan_maria_kingon_steer_2009, title={Narrowband Barium Strontium Titanate (BST) Tunable Bandpass Filters at X-band}, ISBN={["978-1-4244-2803-8"]}, ISSN={["0149-645X"]}, DOI={10.1109/mwsym.2009.5165883}, abstractNote={A 3rd-order combline tunable filter with very narrow bandwidth at X-band is implemented utilizing ferroelectric barium strontium titanate (BST) interdigitated varactors. The filter and its varactors are integrated on a ceramic substrate together with a simple resistive biasing circuit. Upon the application of a bias voltage ranging from 0 to 90 V the passband of the filter tuned from 8.127 to 9.973 GHz while maintaining a fractional bandwidth of approximately 4.8-5.9 %. Over the tuning band the passband insertion loss varied from 10.7 dB to 7.5 dB while the return loss was better than 15 dB. The tuning ratio is 23 %.}, journal={2009 IEEE/MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM, VOLS 1-3}, author={Feng, Zhiping and Fathelbab, Wael M. and Lam, Peter G. and Haridasan, Vrinda and Maria, Jon-Paul and Kingon, Angus I. and Steer, Michael B.}, year={2009}, pages={1061-+} }
@article{lam_feng_haridasan_kingon_steer_maria_2009, title={The Impact of Metallization Thickness and Geometry for X-Band Tunable Microwave Filters}, volume={56}, ISSN={["1525-8955"]}, DOI={10.1109/TUFFC.2009.1122}, abstractNote={The impact of dc resistance on the performance of X-band filters with ferroelectric varactors was investigated. Two series of combline bandpass filters with specific geometries to isolate sources of conductor losses were designed and synthesized. Combining the changes in filter geometry with microwave measurements and planar filter solver (Sonnet software) simulations quantitatively identified the dependency of insertion loss on overall metallization thickness and local regions of thin metallization. The optimized 8-GHz bandpass filters exhibited insertion losses of 6.8 dB. These filters required 2.5 ¿m of metal thickness (or 3 effective skin depths) to achieve this loss. The trend of loss with thickness indicates diminishing return with additional metal. The integration scheme requires thin regions of metal in the immediate vicinity of the varactors. It is shown through experiment and simulation that short distances (i.e., 15 ¿m) of thin metallization can be tolerated provided that they are located in regions where the resonant microwave current is low.}, number={5}, journal={IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL}, author={Lam, Peter G. and Feng, Zhiping and Haridasan, Vrinda and Kingon, Angus I. and Steer, Michael B. and Maria, Jon-Paul}, year={2009}, month={May}, pages={906–911} }
@article{wilkerson_gard_schuchinsky_steer_2008, title={Electro-Thermal Theory of Intermodulation Distortion in Lossy Microwave Components}, volume={56}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2008.2007084}, abstractNote={An analytic formulation of dynamic electro-thermally induced nonlinearity is developed for a general resistive element, yielding a self-heating circuit model based on a fractional derivative. The model explains the 10 dB/decade slope of the intermodulation products observed in two-tone testing. Two-tone testing at 400 MHz of attenuators, microwave chip terminations, and coaxial terminations is reported with tone spacing ranging from 1 to 100 Hz.}, number={12}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Wilkerson, Jonathan R. and Gard, Kevin G. and Schuchinsky, Alexander G. and Steer, Michael B.}, year={2008}, month={Dec}, pages={2717–2725} }
@article{varma_steer_franzon_2008, title={Improving Behavioral IO Buffer Modeling Based on IBIS}, volume={31}, ISSN={["1521-3323"]}, DOI={10.1109/tadvp.2008.2004995}, abstractNote={High level behavioral modeling is widely used in lieu of low level transistor models to ascertain the behavior of input/output (IO) drivers and receivers. The input output buffer information specification (IBIS) is one of the most widely used methodologies to model IO drivers as it satisfies the basic requirements of a behavioral model such as IP protection, simple structure, fast simulation time, and reasonable accuracy. As driver technology gets increasingly complicated and rise time of input signal gets increasingly smaller, important considerations such as simultaneous switching noise (SSN) becomes a major consideration when simulating multiple IO drivers in the integrated circuit. Unfortunately, IBIS falls short of becoming a complete IO behavioral model when simulating for SSN. This paper addresses the problem by assessing what is missing in IBIS. A method is presented for compensating for the missing information by complimenting the IBIS model with a black box that is simulator independent, without compromising with the speed that IBIS enjoys over the transistor models.}, number={4}, journal={IEEE TRANSACTIONS ON ADVANCED PACKAGING}, author={Varma, Ambrish K. and Steer, Michael and Franzon, Paul D.}, year={2008}, month={Nov}, pages={711–721} }
@article{kriplani_luniya_steer_2008, title={Integrated deterministic and stochastic simulation of electronic circuits: Application to large signal-noise analysis}, volume={21}, ISSN={["1099-1204"]}, DOI={10.1002/jnm.674}, abstractNote={The ability to model the effect of non-negligible levels of white noise superimposed on a carrier is investigated when this signal–noise combination is fed to the input of an MMIC power amplifier. Transient simulation using stochastic differential equations is introduced here to handle large levels of noise of arbitrary frequency characteristics. The effectiveness of the modelling is ascertained by looking at measured gain-compression plots at the output of the amplifier and comparing these with simulated results. It is found that increasing levels of noise introduce increased compression of the output power characteristic. Copyright © 2008 John Wiley & Sons, Ltd.}, number={6}, journal={INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS}, author={Kriplani, Nikhil M. and Luniya, Sonali R. and Steer, Michael B.}, year={2008}, pages={381–394} }
@article{mazzaro_steer_gard_walker_2008, title={Response of RF Networks to Transient Waveforms: Interference in Frequency-Hopped Communications}, volume={56}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2008.2007085}, abstractNote={The long-tail transient responses of a bandpass network to pulsed and switched-tone stimuli are examined and a time-domain closed-form expression of the envelope response is developed. It is shown that the long-tail response leads to interference in frequency-hopping communication systems. Interference, and in particular co-site interference, can result in any radar, communication, or RF sensor system becoming exposed to unintentional pulsed RF signals. In the experimental study, 900-MHz Chebyshev bandpass filters are considered.}, number={12}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Mazzaro, Gregory J. and Steer, Michael B. and Gard, Kevin G. and Walker, Aaron L.}, year={2008}, month={Dec}, pages={2808–2814} }
@article{steer_2007, title={Beyond 3G}, volume={8}, DOI={10.1109/MMW.2007.316254}, abstractNote={Beyond 3G is the official IEEE designation for the next stage of wireless technology that some people call 4G or fourth-generation radio. Over the years, every conceptual shift in wireless technology has been characterized as a generational change. Third generation includes wideband mobile multimedia networks and broadband mixed wireless systems. The mobile systems support variable data rates depending on demand and the level of mobility. Typically 144 kb/s is supported for full vehicular mobility and higher bandwidths for pedestrian levels of mobility. Switched packet radio techniques and wideband CDMA-like systems (as the physical channel is) rather than assigned physical channel schemes (referred to as circuit switched) are required to support this bandwidth-on-demand environment. There are two essential concepts beyond 3G. One of these is the provision of data transmission at rates of 100 Mb/s while mobile and 1 Gb/s while stationary. The other concept is that of pervasive networks where a handset supports many access technologies (e.g., cellular, UMTS, and WiFi) perhaps simultaneously and smoothly transitions between them}, number={1}, journal={IEEE Microwave Magazine}, author={Steer, M.}, year={2007}, pages={76–82} }
@article{fathelbab_steer_2007, title={Design of bandstop filters utilising circuit prototypes}, volume={1}, ISSN={["1751-8725"]}, DOI={10.1049/iet-map:20060147}, abstractNote={A systematic circuit-oriented approach to the design of bandstop filters with pre-defined upper passband characteristics is presented. An experimental filter is built with a fundamental stopband centred at 1.085 GHz and a first spurious stopband centred at 5.4 GHz.}, number={2}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Fathelbab, W. M. and Steer, M. B.}, year={2007}, month={Apr}, pages={523–526} }
@article{gharaibeh_gard_steer_2007, title={Estimation of co-channel nonlinear distortion and SNDR in wireless systems}, volume={1}, ISSN={["1751-8733"]}, DOI={10.1049/iet-map:20070034}, abstractNote={The effective signal-to-noise and distortion ratio (SNDR) at the output of a nonlinear amplifier is defined through the decomposition of the nonlinear output into correlated output and uncorrelated distortion. The analysis is based on the orthogonalisation of the nonlinear behavioual model that allows the accurate estimation of the effective in-band (or co-channel) distortion and hence determination of SNDR. Fundamental issues regarding the evaluation of the effective in-band distortion and its effect on digitally modulated signals are discussed. Simulations of in-band distortion and SNDR of WCDMA signals are verified experimentally using feed-forward cancelation.}, number={5}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Gharaibeh, K. M. and Gard, K. G. and Steer, M. B.}, year={2007}, month={Oct}, pages={1078–1085} }
@article{fathelbab_steer_2007, title={Filter prototypes comprising singlet and/or in-line sections}, volume={94}, ISSN={["0020-7217"]}, DOI={10.1080/00207210701682888}, abstractNote={A synthesis procedure for the design of filter prototypes comprising singlet and/or in-line sections is presented. Each singlet section realizes a finite-frequency transmission zero without requiring frequency-invariant elements at its non-resonating nodes. Prototypes comprised entirely of singlet sections realize either a lowpass or highpass response. These prototypes can also be easily transformed to in-line prototypes through the usage of simple mathematical expressions. The characteristics of an experimental bandpass filter centered at 915 MHz are reported.}, number={10}, journal={INTERNATIONAL JOURNAL OF ELECTRONICS}, author={Fathelbab, W. M. and Steer, M. B.}, year={2007}, pages={925–934} }
@article{katehi_chappell_mohammadi_margomenos_steer_2007, title={Heterogeneous wafer-scale circuit architectures}, volume={8}, ISSN={["1557-9581"]}, DOI={10.1109/MMW.2007.316255}, abstractNote={This article has presented circuit architectures that allow for the 3D integration and on-wafer packaging through the concept of an Si interposer. The presented 3D integration schemes have allowed for the design and fabrication of a fully integrated receiver that performs at 10 GHz. High-Q passives and 3D interconnects allow for the design of low-cost, high-density circuits that also exhibit very high performance}, number={1}, journal={IEEE MICROWAVE MAGAZINE}, author={Katehi, Linda and Chappell, William and Mohammadi, Saeed and Margomenos, Alexandros and Steer, Michael}, year={2007}, month={Feb}, pages={52–69} }
@article{hart_steer_2007, title={Modeling the nonlinear response of multitones with uncorrelated phase}, volume={55}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2007.906462}, abstractNote={Traditional simulation approaches for predicting the frequency-domain response of nonlinear devices to multiple tone excitation enforce correlation of the phases of the individual tones. This is the case with time-domain simulators and transform-based schemes such as Harmonic balance as the waveform must be single valued, thus enforcing correlation. Previous efforts in frequency-domain simulators using the arithmetic operator method (AOM) also produced results in good agreement with measurements for correlated-phase input signals. Here, the AOM is applied to directly determine the spectral response of nonlinear systems to excitation by multiple uncorrelated tones in a single simulation. Verification is provided using measurements of a nonlinear amplifier excited by 15 independent tones and comparison to the average of the ensemble of results from multiple correlated-phase simulations.}, number={10}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Hart, Frank P. and Steer, Michael B.}, year={2007}, month={Oct}, pages={2147–2156} }
@article{hart_luniya_nath_victor_walker_steer_2007, title={Modelling high-order filters in a transient microwave circuit simulator}, volume={1}, ISSN={["1751-8733"]}, DOI={10.1049/iet-map:20060231}, abstractNote={Transient simulation of narrowband bandpass filters used in microwave circuits is challenging because of matrix ill-conditioning. Here, such filters are modelled as the equivalent discrete-time form developed using a bilinear z-transform. The technique has been implemented in a general purpose transient circuit simulator and validated using a 1.7 GHz 5-section coaxial filter with a 0.9% bandwidth.}, number={5}, journal={IET MICROWAVES ANTENNAS & PROPAGATION}, author={Hart, F. P. and Luniya, S. R. and Nath, J. and Victor, A. and Walker, A. and Steer, M. B.}, year={2007}, month={Oct}, pages={1024–1028} }
@article{buff_nath_steer_2007, title={Origin of the half-wavelength errors in microwave measurements using through-line calibrations}, volume={56}, ISSN={["1557-9662"]}, DOI={10.1109/TIM.2007.904490}, abstractNote={ The through–line calibration family uses measurements of a through connection and an inserted line to determine the propagation constant of the line. This is typically used with measurements of a reflect standard to characterize fixturing errors. Subsequently, the S-parameters of a device under test are de-embedded. Measurement uncertainties occur at frequencies where the length of the line standard is an odd multiple of a half-wavelength. The origin of these errors is identified as fixture inconsistencies between the through and the line measurements. Error formulations are developed, and it is shown that a small fixturing error can be accounted for as a multiplicative transmission error. An error sensitivity function is developed and highlights the importance of fixture repeatability. }, number={5}, journal={IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT}, author={Buff, P. Mark and Nath, Jayesh and Steer, Michael B.}, year={2007}, month={Oct}, pages={1610–1615} }
@article{victor_steer_2007, title={Reflection coefficient shaping of a 5-GHz voltage-tuned oscillator for improved tuning}, volume={55}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2007.909140}, abstractNote={Negative resistance voltage-controlled oscillators (VCOs) are systematically designed to operate with loaded resonator networks that permit stable steady-state oscillation over a specified tuning bandwidth. Circuit parasitics, however, significantly affect tuning behavior and complicate straightforward design. This paper introduces a scheme that compensates for the effect of parasitics by introducing an embedding network that modifies the effective active device reflection coefficient and thus enables conventional one-port oscillator design techniques to be used. A common-base SiGe HBT VCO operating from 4.4 to 5.5 GHz demonstrates the technique. Phase noise is better than -85 dBc/Hz at 10-kHz offset from the carrier and the second harmonic is less than -20 dBc, while higher order harmonics are less than -40 dBc. The voltage-tuned oscillator demonstrates an oscillator figure-of-merit of at least -182 dBc/Hz over a 800-MHz tuning range. The phase-noise-bandwidth (in megahertz) product is -159 dBc/Hz.}, number={12}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Victor, Alan and Steer, Michael B.}, year={2007}, month={Dec}, pages={2488–2494} }
@article{walker_steer_gard_2006, title={A vector intermodulation analyzer applied to behavioral modeling of nonlinear amplifiers with memory}, volume={54}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2006.872810}, abstractNote={A large signal vector intermodulation network analyzer with a dynamic range of 90 dB and phase resolution of better than 2/spl deg/ is reported. The analyzer is used in conjunction with a multislice behavioral model to characterize memory effects in three different RF power amplifiers: an MOSFET instrumentation amplifier, a multistage GaAs/silicon-based broadband microwave integrated-circuit amplifier, and an SiGe HBT monolithic-microwave integrated-circuit amplifier. The multislice behavioral model architecture builds on conventional single-tone AM-AM and AM-PM modeling extended to capture long-term memory effects that are characterized by asymmetric intermodulation distortion (IMD). Phase asymmetries of upper and lower IMD are captured. A systematic procedure for extracting the model is presented.}, number={5}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Walker, Aaron and Steer, Michael and Gard, Kevin G.}, year={2006}, month={May}, pages={1991–1999} }
@article{jang_walker_gard_steer_2006, title={Capturing asymmetrical spectral regrowth in RF systems using a MultiSlice behavioral model and enhanced envelop transient analysis}, volume={16}, ISSN={["1099-047X"]}, DOI={10.1002/mmce.20160}, abstractNote={Nonlinear distortion in RF and microwave systems results in spectral regrowth of digitally modulated signals. The distortion above and below the main channel can be at different levels and this is attributed to baseband effects. This article presents a new multislice behavioral-model architecture that captures this asymmetry and can be implemented in a variety of circuit simulators, including SPICE, harmonic balance (HB), envelope transient (ET), and system simulators. The work is experimentally validated using an HBT power amplifier at 2.5 GHz driven by a WCDMA signal. The model is used with envelope transient circuit simulation which is enhanced to accommodate an arbitrary baseband transfer function. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.}, number={4}, journal={INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING}, author={Jang, Wonhoon and Walker, Aaron and Gard, Kevin and Steer, Michael B.}, year={2006}, month={Jul}, pages={400–407} }
@article{walker_steer_gard_2006, title={Capturing asymmetry in distortion of an RF system using a multislice behavioral model}, volume={16}, DOI={10.1109/LMWC.2006.0872114}, number={4}, journal={IEEE Microwave and Wireless Components Letters}, author={Walker, A. and Steer, M. and Gard, K.}, year={2006}, pages={212–214} }
@article{buff_steer_lazzi_2006, title={Cole-Cole dispersion models for aqueous gelatin-syrup dielectric composites}, volume={44}, ISSN={["0196-2892"]}, DOI={10.1109/TGRS.2005.861409}, abstractNote={A dielectric composite is developed with permittivity ranging from 8 to 75 with selectable conductive and dielectric losses. The composite comprises gelatin, high fructose corn syrup (HFCS), NaCl, and water, and can be used to model soils, loams, and sands in the 200-MHz to 20-GHz range. A single-term Cole-Cole dispersion equation is developed with frequency-independent parameters being functions of component concentrations. Fits are provided for various soil samples and surrogate concentrations.}, number={2}, journal={IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING}, author={Buff, PM and Steer, MB and Lazzi, G}, year={2006}, month={Feb}, pages={351–355} }
@article{nath_fathelbab_lam_ghosh_aygun_gard_maria_kingon_steer_2006, title={Discrete Barium Strontium Titanate (BST) thin-film interdigital varactors on alumina: Design, fabrication, characterization, and applications}, ISBN={["978-0-7803-9541-1"]}, ISSN={["2576-7216"]}, DOI={10.1109/mwsym.2006.249652}, abstractNote={Discrete Barium Strontium Titanate (BST) thin-film capacitors in industry standard 0603 footprint are introduced and characterized. BST capacitors have a voltage-dependent permittivity, enabling BST thin-film capacitors to be used as tuning elements in frequency agile devices. The capacitance changed by 1.5: 1 at 35 V (116 kV/cm) bias. The temperature dependence of the capacitance was measured to be less than ± 20 % from -100°C to +100°C. A 2nd-order tunable combline bandpass filter on FR4 substrate has been implemented using the discrete BST varactors. The filter showed a center frequency tuning of 22% from 2.14 GHz to 2.61 GHz upon application of 130 V (433 kV/cm) bias. The zero-bias insertion loss was 4.9 dB which decreased to 2.9 dB at the high bias state. The return loss was better than 11 dB over the tuning range. Nonlinear characterization of the filter using two-tone test and a digitally-modulated CDMA 2000 signal showed an IP3 of +32 dBm and an ACPR of better than -50 dBc up to 26 dBm of input power, respectively.}, journal={2006 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-5}, author={Nath, Jayesh and Fathelbab, Wael M. and Lam, Peter G. and Ghosh, Dipankar and Aygun, Seymen and Gard, Kevin G. and Maria, J. -P. and Kingon, Angus I. and Steer, Michael B.}, year={2006}, pages={552–555} }
@article{steer_2006, title={Editorial: Mini-special issue on radio frequency integrated circuits}, volume={54}, ISSN={["0018-9480"]}, DOI={10.1109/tmtt.2005.861673}, number={1}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Steer, MB}, year={2006}, month={Jan}, pages={3–3} }
@article{gharaibeh_gard_steer_2006, title={In-band distortion of multisines}, volume={54}, ISSN={["1557-9670"]}, DOI={10.1109/tmtt.2006.879170}, abstractNote={Multisine signals are shown to be useful for estimating distortion of communication signals. In particular, a generalized approach for the evaluation of effective in-band distortion in a nonlinear amplifier using multisine excitation is presented. The output of the nonlinearity is represented as the sum of uncorrelated components by the transformation of a behavioral model. Simulated and measured results are presented for code-division multiple-access signals}, number={8}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Gharaibeh, Khaled M. and Gard, Kevin G. and Steer, Michael B.}, year={2006}, month={Aug}, pages={3227–3236} }
@article{luniya_gard_steer_2006, title={Modeling nonlinear distortion of ultra wideband signals at X-band}, volume={16}, ISSN={["1558-1764"]}, DOI={10.1109/LMWC.2006.875588}, abstractNote={Nonlinear distortion in the adjacent channels of an X-band amplifier driven by an ultra-wideband digitally-modulated carrier is analyzed. Statistical properties of the input signal with a complex power series-based behavioral model of the amplifier are used to calculate the output power spectrum. Comparisons are made between measured and predicted adjacent channel power rejection for the X-band monolithic microwave integrated circuit.}, number={6}, journal={IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS}, author={Luniya, Sonali and Gard, Kevin G. and Steer, Michael B.}, year={2006}, month={Jun}, pages={381–383} }
@article{victor_nath_ghosh_boyette_maria_steer_kingon_stauf_2006, title={Noise characteristics of an oscillator with a barium strontium titanate (BST) varactor}, volume={153}, ISSN={["1350-2417"]}, DOI={10.1049/ip-map:20050068}, abstractNote={The phase noise of an oscillator with a thin-film barium strontium titanate (BST) capacitive tuning element, or varactor, is characterised and benchmarked against the same oscillator with a silicon semiconductor junction varactor. Phase noise tracks closely with varactor Q within a specific voltage range as expected. Compared to the semiconductor varactor-based oscillator, the BST-based oscillator demonstrates reduced phase noise degradation near zero volts, but greater phase noise degradation when operated near breakdown.}, number={1}, journal={IEE PROCEEDINGS-MICROWAVES ANTENNAS AND PROPAGATION}, author={Victor, A and Nath, J and Ghosh, D and Boyette, B and Maria, JP and Steer, MB and Kingon, AI and Stauf, GT}, year={2006}, month={Feb}, pages={96–102} }
@article{carvalho_pedro_jang_steer_2006, title={Nonlinear RF circuits and systems simulation when driven by several modulated signals}, volume={54}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2005.862713}, abstractNote={The simulation of nonlinear RF circuits and systems driven by digitally modulated signals with a large number of carriers is addressed by combining the envelope transient harmonic balance method with the artificial frequency mapping technique. The co-simulation of low-pass equivalent behavioral models with circuit based models is addressed by simulating the overall wireless communication path. Several application examples are considered, in particular, the modeling of complete wireless communications circuits and systems incorporating the radio channel model.}, number={2}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Carvalho, NB and Pedro, JC and Jang, WH and Steer, MB}, year={2006}, month={Feb}, pages={572–579} }
@article{kriplani_nackashi_amsinck_di spigna_steer_franzon_rick_solomon_reimers_2006, title={Physically based molecular device model in a transient circuit simulator}, volume={326}, ISSN={["1873-4421"]}, DOI={10.1016/j.chemphys.2006.03.003}, abstractNote={Abstract Two efficient, physically based models for the real-time simulation of molecular device characteristics of single molecules are developed. These models assume that through-molecule tunnelling creates a steady-state Lorentzian distribution of excess electron density on the molecule and provides for smooth transitions for the electronic degrees of freedom between the tunnelling, molecular-excitation, and charge-hopping transport regimes. They are implemented in the f REEDA™ transient circuit simulator to allow for the full integration of nanoscopic molecular devices in standard packages that simulate entire devices including CMOS circuitry. Methods are presented to estimate the parameters used in the models via either direct experimental measurement or density-functional calculations. The models require 6–8 orders of magnitude less computer time than do full a priori simulations of the properties of molecular components. Consequently, molecular components can be efficiently implemented in circuit simulators. The molecular-component models are tested by comparison with experimental results reported for 1,4-benzenedithiol.}, number={1}, journal={CHEMICAL PHYSICS}, author={Kriplani, Nikhil M. and Nackashi, David P. and Amsinck, Christian J. and Di Spigna, Neil H. and Steer, Michael B. and Franzon, Paul D. and Rick, Ramon L. and Solomon, Gemma C. and Reimers, Jeffrey R.}, year={2006}, month={Jul}, pages={188–196} }
@article{fathelbab_steer_2006, title={Tapped marchand baluns for matching applications}, volume={54}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2006.875821}, abstractNote={Compact three-terminal structures with integrated matching and balun functionality are presented. The structures are in the form of tapped Marchand baluns and possess prescribed immittance profiles at either their single-ended or balanced ports. These prescribed profiles are important in ensuring stability of active circuits. Tapping the balanced resonators of the baluns enables the realization of an extremely wide range of load-to-source impedance or admittance ratios at no increase in overall size. Designs and implementations of two tapped Marchand baluns with octave bandwidths centered at 500 MHz are presented}, number={6}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Fathelbab, Wael M. and Steer, Michael B.}, year={2006}, month={Jun}, pages={2543–2551} }
@article{victor_steer_2006, title={Transceiver cascade system analysis and design via a contribution method}, volume={16}, ISSN={["1099-047X"]}, DOI={10.1002/mmce.20154}, abstractNote={An approach to the design of cascade receiver and transmitter systems for maximum spurious-free dynamic range (SFDR) is introduced. The contribution method developed here provides a good initial assignment of noise figure, gain, and linearity requirement to individual stages and enables informed assessment of trade-offs during system design. Application of the approach to the design of a receiver preselector cascade for maximum SFDR is discussed. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.}, number={4}, journal={INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING}, author={Victor, Alan M. and Steer, Michael B.}, year={2006}, month={Jul}, pages={338–345} }
@article{ghosh_laughlin_nath_kingon_steer_maria_2006, title={Tunable high-quality-factor interdigitated (Ba, Sr)TiO3 capacitors fabricated on low-cost substrates with copper metallization}, volume={496}, ISSN={["0040-6090"]}, DOI={10.1016/j.tsf.2005.09.025}, abstractNote={Interdigitated capacitors containing the field-tunable ferroelectric Ba0.75Sr0.25TiO3, polycrystalline alumina substrates, and copper metallization have been fabricated. Dielectric layers were prepared by magnetron sputtering, while the Cu metallization was evaporated. The dielectric tunability of the Ba0.75Sr0.25TiO3 was 40% at an applied electric field of 12 V/μm. This corresponds to a 3-μm electrode gap width and a 35 V dc bias. Low-frequency (1 MHz) loss tangent measurements indicate a dielectric Q (quality factor) of ∼100 while microwave measurements reveal a zero bias device Q of ∼30 at 26 GHz. These values are comparable or superior to numerous reports of barium strontium titanate interdigitated capacitors prepared using single crystalline substrates and noble metallization. As such, this technology is significantly less expensive and more amenable to large-volume manufacturing.}, number={2}, journal={THIN SOLID FILMS}, author={Ghosh, D and Laughlin, B and Nath, J and Kingon, AI and Steer, MB and Maria, JP}, year={2006}, month={Feb}, pages={669–673} }
@inproceedings{victor_nath_ghosh_aygun_nagy_maria_kingon_steer_2006, title={Voltage controlled GaN on Si HFET power oscillator using thin?film ferroelectric varactor tuning}, DOI={10.1109/eumc.2006.281206}, abstractNote={A 1.6 GHz power oscillator with a GaN-on-Si heterostructure field effect transistor (HFET) is reported. The voltage-controlled oscillator used a thin-film barium strontium titanate (BST) interdigital varactor as the tuning element. The surface-mount varactor was fabricated using sputtered BST film and copper metallization on alumina. An output power of 1.6 W (32 dBm) is obtained with a DC conversion efficiency of 25.5%. Flat tuning sensitivity of 500 kHz/V, 49 MHz linear frequency tuning, and power flatness of better than 0.5 dB are obtained with 0-100 V tuning voltage. The maximum oscillator phase noise is -81.4 dBc/Hz at 100 kHz offset..}, booktitle={Proceedings of the 36th European Microwave Conference, (EuMW2006), Manchester, UK}, publisher={London: Horizon House}, author={Victor, A. and Nath, J. and Ghosh, D. and Aygun, S. and Nagy, W. and Maria, J.-P. and Kingon, A. I. and Steer, M. B.}, year={2006}, pages={87–90} }
@article{fathelbab_steer_2005, title={A reconfigurable bandpass filter for RF/microwave multifunctional systems}, volume={53}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2005.843502}, abstractNote={A network prototype suitable for reconfigurable filters with imaginary-axis transmission zeros is presented. The prototype is synthesized using classical cascade synthesis. Reconfiguration of the transmission zeros is implemented entirely by tunable capacitors. The measured performance of a narrow-band reconfigurable bandpass filter realized in a planar combline using varactor diodes demonstrates the principle.}, number={3}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Fathelbab, WM and Steer, MB}, year={2005}, month={Mar}, pages={1111–1116} }
@article{nath_ghosh_fathelbab_maria_kingon_franzon_steer_2005, title={A tunable combline bandpass filter using Barium Strontium Titanate interdigital varactors on an alumina substrate}, ISBN={["0-7803-8845-3"]}, ISSN={["2576-7216"]}, DOI={10.1109/mwsym.2005.1516670}, abstractNote={Barium strontium titanate (BST) has a field-dependent permittivity that enables it to be used as a dielectric in a voltage-tunable capacitor or varactor. A tunable combline bandpass filter was designed and characterized using BST varactors fabricated on a polycrystalline alumina substrate with copper metallization and is 14 mm /spl times/ 14 mm in size. The center frequency of the filter varies from 1.6 to 2.0 GHz with the application of 200 V tuning voltage. A 25% tuning range was achieved using tuning field strength of 300 kV/cm. The zero bias insertion loss was 6.6 dB and this decreased to 4.3 dB at the high bias state. The return loss was better than 10 dB.}, journal={2005 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM, VOLS 1-4}, publisher={Piscataway, NJ: IEEE}, author={Nath, J and Ghosh, D and Fathelbab, W and Maria, JP and Kingon, AI and Franzon, PD and Steer, MB}, year={2005}, pages={595–598} }
@article{nath_ghosh_maria_kingon_fathelbab_franzon_steer_2005, title={An electronically tunable microstrip bandpass filter using thin-film barium-strontium-titanate (BST) varactors}, volume={53}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2005.854196}, abstractNote={A tunable third-order combline bandpass filter using thin-film barium-strontium-titanate varactors and fabricated on a sapphire substrate is reported. Application of 0-200-V bias varied the center frequency of the filter from 2.44 to 2.88 GHz (16% tuning) while achieving a 1-dB bandwidth of 400 MHz. The insertion loss varied from 5.1 dB at zero bias to 3.3 dB at full bias, while the return loss exceeded 13 dB over the range. The third-order intercept of the filter was found to be 41 dBm.}, number={9}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Nath, J and Ghosh, D and Maria, JP and Kingon, AI and Fathelbab, W and Franzon, PD and Steer, MB}, year={2005}, month={Sep}, pages={2707–2712} }
@article{davis_wilson_mick_xu_hua_mineo_sule_steer_franzon_2005, title={Demystifying 3D ICs: The procs and cons of going vertical}, volume={22}, ISSN={["1558-1918"]}, DOI={10.1109/MDT.2005.136}, abstractNote={This article provides a practical introduction to the design trade-offs of the currently available 3D IC technology options. It begins with an overview of techniques, such as wire bonding, microbumps, through vias, and contactless interconnection, comparing them in terms of vertical density and practical limits to their use. We then present a high-level discussion of the pros and cons of 3D technologies, with an analysis relating the number of transistors on a chip to the vertical interconnect density using estimates based on Rent's rule. Next, we provide a more detailed design example of inductively coupled interconnects, with measured results of a system fabricated in a 0.35-/spl mu/m technology and an analysis of misalignment and crosstalk tolerances. Lastly, we present a case study of a fast Fourier transform (FFT) placed and routed in a 0.18-/spl mu/m through-via silicon-on-insulator (SOI) technology, comparing the 3D design to a traditional 2D approach in terms of wire length and critical-path delay.}, number={6}, journal={IEEE DESIGN & TEST OF COMPUTERS}, author={Davis, WR and Wilson, J and Mick, S and Xu, M and Hua, H and Mineo, C and Sule, AM and Steer, M and Franzon, PD}, year={2005}, pages={498–510} }
@article{steer_2005, title={Editorial - State of this TRANSACTIONS}, volume={53}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2005.845776}, number={4}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Steer, MB}, year={2005}, month={Apr}, pages={1121–1123} }
@article{pant_neifeld_steer_kanj_cangellaris_2005, title={Electrical package impact on VCSEL-based optical interconnects}, volume={245}, ISSN={["1873-0310"]}, DOI={10.1016/j.optcom.2004.10.017}, abstractNote={A new CAD tool fREEDA® based on state variable approach and universal error concept is presented for modelling and simulating systems where physical domains such as electrical, thermal, and optical interact with each other. A single implementation of device equations in fREEDA® can be used with different analysis types such as transient and harmonic balance, etc. To demonstrate the multi-physics capabilities of fREEDA®, we present a study of the impact of electrical packages on the source module performance in multi-gigabit per second vertical cavity surface emitting laser (VCSEL)-based optical interconnects. The effect of various operating conditions such as bias/drive level and driver configuration are studied. We consider electrical packages such as printed wire board, thin-film and flip-chip in our study. A comparison of VCSELs with stripe lasers is also presented.}, number={1-6}, journal={OPTICS COMMUNICATIONS}, author={Pant, R and Neifeld, MA and Steer, MB and Kanj, H and Cangellaris, A}, year={2005}, month={Jan}, pages={315–332} }
@article{fathelbab_steer_2005, title={Four-port microwave networks with intrinsic broad-band suppression of common-mode signals}, volume={53}, DOI={10.1108/TMTT.2005.847046}, number={5}, journal={IEEE Transactions on Microwave Theory and Techniques}, author={Fathelbab, W. M. and Steer, M. B.}, year={2005}, pages={1569–1575} }
@article{ghosh_laughlin_nath_kingon_steer_maria_2005, title={High Q (Ba, Sr) TiO3 interdigitated capacitors fabricated on low cost polycrystalline alumina substrates with copper metallization}, volume={26}, DOI={10.1002/9780470291252.ch13}, abstractNote={Barium Strontium Titanate (BST) ferroelectric thin films are attractive for radio frequency and microwave applications. However, for many non-military uses, the high cost of conventionally processed devices is a limitingfactor. This high cost stems from the use of single-crystalline sapphire, MgO, or LaAlO 3 substrates and Pt or Au metallization commonly used. Here we present a device process and materials complement offering a low cost alternative. Planar interdigitated capacitors Ba 0 . 7 5 Sr 0 . 2 5 TiO 3 (BST) thin films with chromium/copper top electrodes were fabricated on polycrystalline alumina substrates using a single step photolithographic technique and lift-off. RF magnetron sputtering was used for fabrication of BST thin films while Cu thin films were thermally evaporated The dielectric tunability of the Ba 0 . 7 5 Sr 0 . 2 5 TiO 3 IDCs was 40 % for an applied electric field of 120 kV/cm, which corresponds to 3 μm electrode gap spacing and a 35 volt dc bias. Low frequency (1MHz) loss measurements reveal a dielectric Q ∼ 100 while a device Q of ∼ 30 is obtained at 26 GHz. The reduction of Q between 0.1 and 26 GHz can be attributed to the metallization. Leakage current measurements of the BST planar varactors show current densities of 1.0 x 10 - 6 A / cm 2 for an electric field of 100 kV/cm. These dielectric characteristics (tunability and Q value) are comparable to numerous reports of IDCs with BST films prepared on expensive single crystalline substrates using noble metallization. As such, this technology is significantly less expensive, and amenable to large volume manufacturing.}, number={5}, journal={Ceramic Engineering and Science Proceedings}, author={Ghosh, D. and Laughlin, B. J. and Nath, J. and Kingon, A. I. and Steer, M. B. and Maria, J. P.}, year={2005}, pages={125–132} }
@article{steer_2005, title={Mini-special issue on Asia-Pacific Microwave Conference - Guest editorial}, volume={53}, ISSN={["0018-9480"]}, DOI={10.1109/TMTT.2005.854222}, number={9}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Steer, MB}, year={2005}, month={Sep}, pages={2649–2649} }
@article{gharaibeh_steer_2005, title={Modeling distortion in multichannel communication systems}, volume={53}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2005.847064}, abstractNote={A behavioral modeling technique suited to capturing the response of wide-band multifunctional and multichannel amplifiers is introduced. The technique is based on the three-box approximation of the Volterra model and takes into account the dependence of the amplifier characteristics on frequency. The model is coupled with a new nonlinear statistical analysis, which enables accurate estimation of intermodulation and cross-modulation distortions of multiple digitally modulated signals. The model parameters can be obtained using simple measurements.}, number={5}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Gharaibeh, KM and Steer, MB}, year={2005}, month={May}, pages={1682–1692} }
@article{fathelbab_steer_2005, title={New classes of miniaturized planar Marchand baluns}, volume={53}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2005.845707}, abstractNote={Three new classes of miniaturized Marchand balun are defined based on the synthesis of filter prototypes. They are suitable for mixed lumped-distributed planar realizations with small size resulting from transmission-line resonators being a quarter-wavelength long at frequencies higher than the passband center frequency. Each class corresponds to an S-plane bandpass prototype derived from the specification of transmission zero locations. A tunable 50:100-/spl Omega/ balun is realized at 1 GHz to demonstrate the advantages of the approach presented here.}, number={4}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Fathelbab, WM and Steer, MB}, year={2005}, month={Apr}, pages={1211–1220} }
@article{carvalho_pedro_jang_steer_2005, title={Nonlinear simulation of mixers for assessing system-level performance}, volume={15}, ISSN={["1099-047X"]}, DOI={10.1002/mmce.20091}, abstractNote={This article deals with nonlinear simulation methods intended to evaluate the impact of mixer nonidealities on the performance of a wireless system. Behavioral models capable of accurately describing the mixer's nonlinear dynamic features at the system level are currently unavailable. The possibility of using alternative circuit analysis techniques to reach this goal is discussed. After a brief review of existing mixer analysis methods, the focus is directed to the techniques amenable to efficiently handling periodic carriers modulated by complex stochastic signals. In particular, it is shown how multi-envelope transient methods coupled with a three-dimensional harmonic-balance engine can model a nonlinear dynamic mixer excited by a modulated RF signal accompanied by a strong adjacent channel interferer and with a local oscillator corrupted by phase noise. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.}, number={4}, journal={INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING}, author={Carvalho, NB and Pedro, JC and Jang, W and Steer, MB}, year={2005}, month={Jul}, pages={350–361} }
@article{fathelbab_steer_2005, title={Parallel-coupled line filters with enhanced stopband performances}, volume={53}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2005.859871}, abstractNote={A new class of parallel-coupled line filters with broad stopband response is introduced. The design is based on the synthesis of bandpass prototypes with pre-defined upper stopband characteristics. The new filters have uniform- and stepped-impedance resonators, some of which are loaded by open-circuited stubs at their open-circuited ends. A seventh-order filter implementation is presented with a fundamental passband centered at 1 GHz. The measured wide-band transmission characteristic of the filter demonstrated a broad upper stopband and was in agreement with simulations. The performance of the new filter is also compared with the characteristic of a conventionally designed filter to highlight the advantages of the proposed design method.}, number={12}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Fathelbab, WM and Steer, MB}, year={2005}, month={Dec}, pages={3774–3781} }
@article{gard_larson_steer_2005, title={The impact of RF front-end characteristics on the spectral regrowth of communications signals}, volume={53}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2005.848801}, abstractNote={The nonlinear characteristic of an RF front-end results in in-band distortion and spectral regrowth of digitally modulated signals with distortion being dependent on the statistical variation of the signal. In this paper, the interaction of the nonlinear response with the signal is explored using a time-averaged autocorrelation analysis applied to several limiter-amplifier models having characteristics ranging from soft-to-hard amplitude limiting. The analysis is verified by comparing measured and predicted adjacent channel power rejection for a code-division multiple-access amplifier.}, number={6}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Gard, KG and Larson, LE and Steer, MB}, year={2005}, month={Jun}, pages={2179–2186} }
@article{steer_2005, title={Untitled}, volume={53}, ISSN={["0018-9480"]}, DOI={10.1109/tmtt.2004.839957}, number={1}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Steer, M}, year={2005}, month={Jan}, pages={3–3} }
@article{victor_nath_ghosh_boyette_maria_steer_kingon_stauf_2004, title={A voltage controlled oscillator using Barium strontium titanate (BST) thin film varactor}, ISBN={["0-7803-8451-2"]}, DOI={10.1109/rawcon.2004.1389079}, abstractNote={Barium strontium titanate (BST) has a field-dependent permittivity and can be used as a dielectric in voltage tunable capacitors or varactors. These BST-based varactors are passive devices and have significantly different properties compared to semiconductor varactors. A voltage tunable oscillator using a BST thin film varactor was designed and characterized. The frequency of oscillation varied from 34.8 MHz to 44.5 MHz (28% tuning) upon application of 7 V tuning voltage. The VCO gain was 1.38 MHz/V and the 2nd harmonic was over 23 dB below the fundamental throughout the tuning range.}, journal={RAWCON: 2004 IEEE RADIO AND WIRELESS CONFERENCE, PROCEEDINGS}, author={Victor, A and Nath, J and Ghosh, D and Boyette, B and Maria, JP and Steer, MB and Kingon, AI and Stauf, GT}, year={2004}, pages={91–94} }
@article{mohan_choi_mick_hart_chandrasekar_cangellaris_franzon_steer_2004, title={Causal reduced-order modeling of distributed structures in a transient circuit simulator}, volume={52}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2004.834588}, abstractNote={Fosters' canonical representation of the transfer characteristic of a linear system is the key to causal fully convergent incorporation of distributed structures in transient circuit simulators. The implementation of the Foster's model in the fREEDA circuit simulator is reported and the modeling of a two-port coupled inductor is presented as an example.}, number={9}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Mohan, R and Choi, MJ and Mick, SE and Hart, FP and Chandrasekar, K and Cangellaris, AC and Franzon, PD and Steer, MB}, year={2004}, month={Sep}, pages={2207–2214} }
@article{fathelbab_steer_2004, title={Distributed biasing of differential RF circuits}, volume={52}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2004.827048}, abstractNote={A distributed balun is presented as an alternative to inductor-based biasing of active differential circuits. The new scheme has broad bandwidth with low loss and is suited to broad-band multifunctional RF and microwave circuits. Additionally, the distributed biasing circuit discriminates between differential and common-mode signals leading to high common-mode rejection. Measured gains, centered at 580 MHz, of a selected pseudodifferential amplifier using the new biasing circuit confirm the underlying theory.}, number={5}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Fathelbab, WM and Steer, MB}, year={2004}, month={May}, pages={1565–1572} }
@inproceedings{nath_ghosh_maria_steer_kingon_stauf_2004, title={Microwave properties of BST thin film interdigital capacitors on low cost alumina substrates}, ISBN={1580539920}, booktitle={Proceedings of the 34th European Microwave Conference (EuMc), Amsterdam}, publisher={London: Horizon House}, author={Nath, J. and Ghosh, D. and Maria, J.-P. and Steer, M. B. and Kingon, A. I. and Stauf, G. T.}, year={2004}, pages={1497–1500} }
@article{steer_2004, title={Mini-Special, Issue on the 2004 IEEE Mtt-S International Microwave Symposium - Early Papers}, volume={52}, ISSN={["0018-9480"]}, DOI={10.1109/TMTT.2004.837338}, number={11}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Steer, M}, year={2004}, month={Nov}, pages={2457–2457} }
@article{steer_2004, title={Mini-special issue on terahertz electronics - Editorial}, volume={52}, ISSN={["0018-9480"]}, DOI={10.1109/TMTT.2004.835907}, number={10}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Steer, M}, year={2004}, month={Oct}, pages={2337–2337} }
@article{steer_2004, title={Mini-special issue on the 2003 IEEE MTT-S International Microwave Symposium}, volume={52}, ISSN={["0018-9480"]}, DOI={10.1109/TMTT.2004.823530}, number={3}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Steer, MB}, year={2004}, month={Mar}, pages={741–742} }
@article{liu_suryanarayanan_nath_mohammadi_katehi_steer_2004, title={Toroidal inductors for radio-frequency integrated circuits}, volume={52}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2003.822019}, abstractNote={Toroidal inductors achieve low loss by constraining magnetic flux to a well-defined path and away from ground planes and semiconducting substrates. This paper presents a micromachined implementation of the toroidal inductor, with focus primarily on microwave integrated circuits on a low-resistivity silicon wafer achieving a Q of 22 and a self-resonant frequency greater than 10 GHz. A verified analytic model is developed.}, number={2}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Liu, WY and Suryanarayanan, J and Nath, J and Mohammadi, S and Katehi, LPB and Steer, MB}, year={2004}, month={Feb}, pages={646–654} }
@article{hicks_yakovlev_steer_2003, title={Aperture-coupled stripline-to-waveguide transitions for spatial power combining}, number={2003 Nov}, journal={Applied Computational Electromagnetics Society Journal}, author={Hicks, C. W. and Yakovlev, A. B. and Steer, M. B.}, year={2003}, month={Nov}, pages={33–40} }
@article{gharaibeh_steer_2003, title={Characterization of cross modulation in multichannel amplifiers using a statistically based behavioral modeling technique}, volume={51}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2003.819195}, abstractNote={A statistically based modeling technique is developed for characterizing in-band and out-of-band intermodulation and cross-modulation distortions in multichannel amplifier environments. The model is based on a new multiple envelope memoryless behavioral model that captures the black-box characteristics of multichannel amplifiers. A power amplifier with a two code-division multiple-access channel signal is characterized experimentally and verifies the approach.}, number={12}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Gharaibeh, KM and Steer, MB}, year={2003}, month={Dec}, pages={2434–2444} }
@article{hart_stephenson_chang_gharaibeh_johnson_steer_2003, title={Mathematical foundations of frequency-domain modeling of nonlinear circuits and systems using the arithmetic operator method}, volume={13}, ISSN={["1096-4290"]}, DOI={10.1002/mmce.10108}, abstractNote={The arithmetic operator method (AOM) is a method for performing arithmetic operations on one or more signals that are described by their spectra. By extension, any analytic functional operation on the signals can be performed in the frequency domain using matrix-vector operations. The mathematical foundation of AOM is presented as a numerically efficient convolution-like procedure in this article. It is directly applicable to the behavioral modeling of nonlinear RF and microwave circuits and systems. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13, 473–495, 2003.}, number={6}, journal={INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING}, author={Hart, FP and Stephenson, DG and Chang, CR and Gharaibeh, K and Johnson, RG and Steer, MB}, year={2003}, month={Nov}, pages={473–495} }
@article{yakovlev_lukic_elsherbeni_smith_steer_2003, title={Meander-slot and U-slot antenna arrays for wide-band spatial power combiners}, volume={13}, ISSN={["1531-1309"]}, DOI={10.1109/LMWC.2003.810125}, abstractNote={In this work, we present a multilayered waveguide transition containing several interacting printed antenna arrays for spatial power combining applications. Narrow-band resonant rectangular slot antennas used in earlier designs are replaced by meander-slot antennas and their modifications, in order to increase the frequency bandwidth and efficiency of the system. Numerical results for finite arrays of meander-slot and U-slot antennas show significant advantages in scattering characteristics in comparison to traditionally used rectangular slot antenna arrays.}, number={3}, journal={IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS}, author={Yakovlev, AB and Lukic, MV and Elsherbeni, AZ and Smith, CE and Steer, MB}, year={2003}, month={Mar}, pages={125–127} }
@article{lukic_yakovlev_elsherbeni_smith_steer_2003, title={Printed antenna design for broadband waveguide-based spatial power combiners}, volume={36}, ISSN={["0895-2477"]}, DOI={10.1002/mop.10778}, abstractNote={Design of broadband printed antennas, including the finite arrays of interacting patch, U-strip, U-slot, and meander slot antennas, are presented for applications in waveguide-based spatial power combiners operating at X-band. The effect of several antenna design parameters on antenna bandwidth performance is investigated in this paper. The antenna designs presented show significant advantages in their scattering characteristics compared to rectangular patch and slot antennas traditionally used in spatial power combiners. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 411–415, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10778}, number={5}, journal={MICROWAVE AND OPTICAL TECHNOLOGY LETTERS}, author={Lukic, MV and Yakovlev, AB and Elsherbeni, AZ and Smith, CE and Steer, MB}, year={2003}, month={Mar}, pages={411–415} }
@article{steer_bandler_snowden_2002, title={Computer-aided design of RF and microwave circuits and systems}, volume={50}, ISSN={["1557-9670"]}, DOI={10.1109/22.989983}, abstractNote={The history of RF and microwave computer-aided engineering is documented in the annals of the IEEE Microwave Theory and Techniques Society. The era began with elaborate analytically based models of microwave components and simple computer-aided techniques to cascade, cascode, and otherwise connect linear component models to obtain the responses of linear microwave circuits. Development has become rapid with computer-oriented microwave practices addressing complex geometries and with the ability to globally model and optimize large circuits. The pursuit of accurate models of active devices and of passive components continues to be a key activity.}, number={3}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Steer, MB and Bandler, JW and Snowden, CM}, year={2002}, month={Mar}, pages={996–1005} }
@article{batty_christoffersen_yakovlev_whitaker_mortazawi_al-zayed_ozkar_ortiz_reano_yang_et al._2002, title={Global coupled EM-electrical-thermal simulation and experimental validation for a spatial power combining MMIC array}, volume={50}, ISSN={["1557-9670"]}, DOI={10.1109/TMTT.2002.805142}, abstractNote={A unique electromagnetic (EM)-electrothermal global simulation tool based on a universal error concept is presented. The advantages of this electrothermal model are illustrated by comparison with a commercial electrothermal circuit simulator. The first description of a fully physical, electrothermal, microwave circuit simulation, based on coupling of the Leeds Physical Model of MESFETs and high electron-mobility transistors, to a microwave circuit simulator, fREEDA (NCSU), is presented. The modeling effort is supported by parallel developments in electrooptic and thermal measurement. The first fully coupled EM-electrothermal global simulation of a large microwave subsystem, here a whole spatial power combining monolithic-microwave integrated-circuit (MMIC) array, is described. The simulation is partially validated by measurements of MMIC array temperature rise and temperature dependent S-parameters. Electrothermal issues for spatial power combiner operation and modeling are discussed. The computer-aided-design tools and experimental characterization described, provide a unique capability for the design of quasi-optical systems and for the exploration of the fundamental physics of spatial power combining devices.}, number={12}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Batty, W and Christoffersen, CE and Yakovlev, AB and Whitaker, JF and Mortazawi, A and Al-Zayed, A and Ozkar, M and Ortiz, SC and Reano, RM and Yang, K and et al.}, year={2002}, month={Dec}, pages={2820–2833} }
@article{tayag_steer_harvey_yakovlev_davis_2002, title={Spatial power splitting and combining based on the Talbot effect}, volume={12}, ISSN={["1531-1309"]}, DOI={10.1109/7260.975718}, abstractNote={The Talbot effect, a multimode interference phenomenon, is investigated as a technique for combining power from solid-state devices in order to generate higher levels of microwave and millimeter-wave power in a process referred to as quasioptical or spatial power combining. We explore the feasibility of using the Talbot effect to implement a 1 /spl times/ 8 power splitter and an 8 /spl times/ 1 power combiner at 94 GHz. We report the first demonstration of the multimode interface phenomenon in a planar waveguide at 8 GHz.}, number={1}, journal={IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS}, author={Tayag, TJ and Steer, MB and Harvey, JF and Yakovlev, AB and Davis, J}, year={2002}, month={Jan}, pages={9–11} }
@article{batty_christoffersen_panks_david_snowden_steer_2001, title={Electrothermal CAD of power devices and circuits with fully physical time-dependent compact thermal modeling of complex nonlinear 3-D systems}, volume={24}, ISSN={["1521-3331"]}, DOI={10.1109/6144.974944}, abstractNote={An original, fully analytical, spectral domain decomposition approach is presented for the time-dependent thermal modeling of complex nonlinear (3-D) electronic systems, from metallized power FETs and MMICs, through MCMs, up to circuit board level. This solution method offers a powerful alternative to conventional numerical thermal simulation techniques, and is constructed to be compatible with explicitly coupled electrothermal device and circuit simulation on CAD timescales. In contrast to semianalytical, frequency space, Fourier solutions involving DFT-FFT, the method presented here is based on explicit, fully analytical, double Fourier series expressions for thermal subsystem solutions in Laplace transform s-space (complex frequency space). It is presented in the form of analytically exact thermal impedance matrix expressions for thermal subsystems. These include double Fourier series solutions for rectangular multilayers, which are an order of magnitude faster to evaluate than existing semi-analytical Fourier solutions based on DFT-FFT. They also include double Fourier series solutions for the case of arbitrarily distributed volume heat sources and sinks, constructed without the use of Green's function techniques, and for rectangular volumes with prescribed fluxes on all faces, removing the adiabatic sidewall boundary condition. This combination allows treatment of arbitrarily inhomogeneous complex geometries, and provides a description of thermal material nonlinearities as well as inclusion of position varying and non linear surface fluxes. It provides a fully physical, and near exact, generalized multiport network parameter description of nonlinear, distributed thermal subsystems, in both the time and frequency domains. In contrast to existing circuit level approaches, it requires no explicit lumped element, RC-network approximation or nodal reduction, for fully coupled, electrothermal CAD. This thermal impedance matrix approach immediately gives rise to minimal boundary condition independent compact models for thermal systems. Implementation of the time-dependent thermal model as N-port netlist elements within a microwave circuit simulation engine, Transim (NCSU), is described. Electrothermal transient, single-tone, two-tone, and multitone harmonic balance simulations are presented for a MESFET amplifier. This thermal model is validated experimentally by thermal imaging of a passive grid array representative of one form of spatial power combining architecture.}, number={4}, journal={IEEE TRANSACTIONS ON COMPONENTS AND PACKAGING TECHNOLOGIES}, author={Batty, W and Christoffersen, CE and Panks, AJ and David, S and Snowden, CM and Steer, MB}, year={2001}, month={Dec}, pages={566–590} }
@article{abdulla_steer_2001, title={Extraction of network parameters in the electromagnetic analysis of planar structures using the method of moments}, volume={49}, ISSN={["1557-9670"]}, DOI={10.1109/22.899966}, abstractNote={Integration of electromagnetic (EM) and circuit analyses for the modeling of spatially distributed microwave and millimeter-wave circuits requires the establishment of ports that are defined in both the circuit and EM realms. Four EM techniques are developed here and contrasted for the extraction of the port network parameters at circuit compatible ports. A full-wave method of-moments EM analysis directly yielding network parameters of a slot-stripline-slot structure is formulated.}, number={1}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Abdulla, MN and Steer, MB}, year={2001}, month={Jan}, pages={94–103} }
@article{rudge_miles_steer_2001, title={Investigation into intermodulation distortion in HEMTs using a quasi-2-D physical model}, volume={49}, ISSN={["1557-9670"]}, DOI={10.1109/22.971615}, abstractNote={The need for both linear and efficient pseudomorphic high electron-mobility transistors (pHEMTs) for modern wireless handsets necessitates a thorough understanding of the origins of intermodulation distortion at the device level. For the first time, the dynamic large-signal internal physical behavior of a pHEMT is examined using a quasi-two-dimensional physical device model. The model accounts fully for device-circuit interaction and is validated experimentally for a two-tone experiment around 5 GHz.}, number={12}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Rudge, PJ and Miles, RE and Steer, MB}, year={2001}, month={Dec}, pages={2315–2321} }
@article{christoffersen_steer_2001, title={State-variable-based transient circuit simulation using wavelets}, volume={11}, ISSN={["1558-1764"]}, DOI={10.1109/7260.916330}, abstractNote={For the first time a state variable transient analysis using wavelets is developed and implemented in a circuit simulator. The formulation is particularly well suited to modeling RF and microwave circuits and is validated by considering a nonlinear transmission line. However, results indicate that still more research is needed to make this method efficient for the simulation of large circuits.}, number={4}, journal={IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS}, author={Christoffersen, CE and Steer, MB}, year={2001}, month={Apr}, pages={161–163} }
@article{yakovlev_ortiz_ozkar_mortazawi_steer_2000, title={A waveguide-based aperture-coupled patch amplifier array - Full-wave system analysis and experimental validation}, volume={48}, ISSN={["0018-9480"]}, DOI={10.1109/22.899032}, abstractNote={In this paper, the full-wave analysis and experimental verification of a waveguide-based aperture-coupled patch amplifier array are presented. The spatial power-combining amplifier array is modeled by the decomposition of the entire system into several electromagnetically coupled modules. This includes a method of moments integral equation formulation of the generalized scattering matrix (GSM) for an N-port waveguide-based patch-to-slot transition; a mode-matching analysis of the GSM for the receiving and transmitting rectangular waveguide tapers; and a finite-element analysis of the waveguide-to-microstrip line junctions. An overall response of the system is obtained by cascading GSMs of electromagnetic structures and the S-parameters of amplifier networks. Numerical and experimental results are presented for the single unit cell and 2/spl times/3 amplifier array operating at X-band. The results are shown for the rectangular aperture-coupled patch array, although the analysis is applicable to structures with arbitrarily shaped planar electric and magnetic surfaces.}, number={12}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Yakovlev, AB and Ortiz, S and Ozkar, M and Mortazawi, A and Steer, MB}, year={2000}, month={Dec}, pages={2692–2699} }
@article{gutierrez_gard_steer_2000, title={Nonlinear cain compression in microwave amplifiers using generalized power-series analysis and transformation of input statistics}, volume={48}, ISSN={["1557-9670"]}, DOI={10.1109/22.873911}, abstractNote={Two methods are presented for the estimation of gain compression generated by a digitally modulated carrier passed through a nonlinear RF circuit. The first one is based on developing an analytical expression for gain compression based on the transformation of input signal statistics. The second one is based on approximated expressions derived from generalized power-series analysis. The techniques are evaluated by comparing measured and predicted gain compression in a CDMA system.}, number={10}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Gutierrez, H and Gard, K and Steer, MB}, year={2000}, month={Oct}, pages={1774–1777} }
@article{christoffersen_mughal_steer_2000, title={Object oriented microwave circuit simulation}, volume={10}, ISSN={["1099-047X"]}, DOI={10.1002/(SICI)1099-047X(200005)10:3<164::AID-MMCE4>3.0.CO;2-K}, abstractNote={An object-oriented microwave circuit simulation environment is described. The design of the program is intended to offer flexibility without sacrificing efficiency. Recent developments in object-oriented techniques and in C++ compilers are used to obtain a flexible and robust system ideally suited to the development of a global modeling strategy for the integration of circuit, field, thermal, and mechanical analyses. The simulation of spatial power combining systems is used as a vehicle to illustrate the architectural developments of the system. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 164–182, 2000.}, number={3}, journal={INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING}, author={Christoffersen, CE and Mughal, UA and Steer, MB}, year={2000}, month={May}, pages={164–182} }
@article{yakovlev_khalil_hicks_mortazawi_steer_2000, title={The generalized scattering matrix of closely spaced strip and slot layers in waveguide}, volume={48}, ISSN={["1557-9670"]}, DOI={10.1109/22.817481}, abstractNote={In this paper, a method-of-moments integral-equation formulation of a generalized scattering matrix (GSM) is presented for the full-wave analysis of interactive planar electric and magnetic discontinuities in waveguide. This was developed to efficiently handle a variety of waveguide-based strip-to-slot transitions, especially on thin substrates. This single matrix formulation replaces the problematic procedure of cascading individual GSM's of an electric (strip) layer, a thin substrate, and a magnetic (slot) layer.}, number={1}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Yakovlev, AB and Khalil, AI and Hicks, CW and Mortazawi, A and Steer, MB}, year={2000}, month={Jan}, pages={126–137} }
@article{khalil_steer_1999, title={A generalized scattering matrix method using the method of moments for electromagnetic analysis of multilayered structures in waveguide}, volume={47}, ISSN={["0018-9480"]}, DOI={10.1109/22.798013}, abstractNote={The method of moments (MoM) in conjunction with the generalized scattering matrix (GSM) approach is proposed to analyze transverse multilayered structures in a metal waveguide. The formulation incorporates ports as an integral part of the GSM formulation, thus, the resulting model can be integrated with circuit analysis. The proposed technique permits the modeling of interactive discontinuities due to the consideration of a large number of modes in the cascade. The GSM-MoM method can be successfully applied to the investigation of a variety of shielded multilayered structures, iris coupled filters, determining the input impedance of probe excited waveguides, and of waveguide-based spatial power combiners.}, number={11}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Khalil, AI and Steer, MB}, year={1999}, month={Nov}, pages={2151–2157} }
@article{khalil_yakovlev_steer_1999, title={Efficient method-of-moments formulation for the modeling of planar conductive layers in a shielded guided-wave structure}, volume={47}, ISSN={["0018-9480"]}, DOI={10.1109/22.788615}, abstractNote={An electric-field integral-equation formulation discretized via the method of moments (MoM) is proposed for the analysis of arbitrarily shaped planar conductive layers in a shielded guided-wave structure. The method results in a generalized scattering matrix (GSM) for the planar structure and can be used with other GSM's, derived using this or other techniques, to model cascaded structures in waveguide. The Kummer transformation is applied to accelerate slowly converging double series expansions of impedance matrix elements obtained in the MoM solution. In this transformation, the quasi-static part associated with a singularity of the electric-type Green's function in the region of a conductive layer is extracted and evaluated in terms of modified Bessel functions, resulting in a dramatic reduction of terms in a double series summation. The proposed technique permits the modeling of a variety of conductive frequency-selective surfaces, including quasi-optical grids and patch arrays for application to spatial power combining.}, number={9}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Khalil, AI and Yakovlev, AB and Steer, MB}, year={1999}, month={Sep}, pages={1730–1736} }
@article{steer_harvey_mink_abdulla_christoffersen_gutierrez_heron_hicks_khalil_mughal_et al._1999, title={Global modeling of spatially distributed microwave and millimeter-wave systems}, volume={47}, ISSN={["1557-9670"]}, DOI={10.1109/22.769316}, abstractNote={Microwave and millimeter-wave systems have generally been developed from a circuit perspective with the effect of the electromagnetic (EM) environment modeled using lumped elements or N-port scattering parameters. The recent development of the local reference node concept coupled with steady-state and transient analyses using state variables allows the incorporation of unrestrained EM modeling of microwave structures in a circuit simulator. A strategy implementing global modeling of electrically large microwave systems using the circuit abstraction is presented. This is applied to the modeling of a quasi-optical power-combining amplifier.}, number={6}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Steer, MB and Harvey, JF and Mink, JW and Abdulla, MN and Christoffersen, CE and Gutierrez, HM and Heron, PL and Hicks, CW and Khalil, AI and Mughal, UA and et al.}, year={1999}, month={Jun}, pages={830–839} }
@article{christoffersen_steer_1999, title={Implementation of the local reference node concept for spatially distributed circuits}, volume={9}, DOI={10.1002/(SICI)1099-047X(199909)9:5<376::AID-MMCE2>3.0.CO;2-M}, abstractNote={Large spatially distributed microwave and millimeter-wave systems involve the interaction of linear and nonlinear circuits with their electromagnetic environment. Here a circuit-level approach to the modeling of circuit-field interactions is developed. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 376–384, 1999}, number={5}, journal={International Journal of RF and Microwave Computer-aided Engineering}, author={Christoffersen, C. E. and Steer, M. B.}, year={1999}, pages={376–384} }
@article{nuteson_steer_nakazawa_mink_1999, title={Near-field and far-field prediction of quasi-optical grid arrays}, volume={47}, ISSN={["0018-9480"]}, DOI={10.1109/22.740066}, abstractNote={Field profiles, equivalent isotropic radiated power (EIRP), beamwidth, and sidelobe levels of a quasi-optical power-combining grid amplifier structure are obtained using a whole-field electromagnetic analysis of a finite structure. This is efficiently obtained using a mixed spectral- and spatial-domain method-of-moments technique. It is seen that edge effects can have a significant effect on system performance.}, number={1}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Nuteson, TW and Steer, MB and Nakazawa, S and Mink, JW}, year={1999}, month={Jan}, pages={6–13} }
@article{christoffersen_ozkar_steer_case_rodwell_1999, title={State-variable-based transient analysis using convolution}, volume={47}, ISSN={["0018-9480"]}, DOI={10.1109/22.769322}, abstractNote={A state-variable-based approach to the impulse response and convolution analysis of distributed microwave circuits is developed. The state-variable approach minimizes computation time and memory requirements. It allows the use of parameterized nonlinear device models, thus improving robustness. Soliton generation on a nonlinear transmission line is considered as an example.}, number={6}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Christoffersen, CE and Ozkar, M and Steer, MB and Case, MG and Rodwell, M}, year={1999}, month={Jun}, pages={882–889} }
@article{khalil_steer_1998, title={Circuit theory for spatially distributed microwave circuits}, volume={46}, ISSN={["0018-9480"]}, DOI={10.1109/22.721154}, abstractNote={A spatially distributed radio-frequency (RF) circuit, microwave, or millimeter-wave circuit does not have a global reference node as required in conventional nodal analysis. Instead, local reference nodes associated with ports are required. This paper adapts modified nodal analysis to accommodate spatially distributed circuits, allowing conventional harmonic balance and transient simulators to be used.}, number={10}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Khalil, AI and Steer, MB}, year={1998}, month={Oct}, pages={1500–1502} }
@article{hicks_hwang_steer_mink_harvey_1998, title={Spatial power combining for two-dimensional structures}, volume={46}, ISSN={["0018-9480"]}, DOI={10.1109/22.681201}, abstractNote={The two-dimensional (2-D) hybrid dielectric slab-beam open and closed waveguide systems are suitable for the design of planar quasi-optical integrated circuits and devices. An open system consisting of an active E-plane amplifier array consisting of Vivaldi-type antennas with MESFET and monolithic microwave integrated circuit (MMIC) devices was investigated. The 4/spl times/1 MESFET amplifier array generated 11 and 4.5 dB of amplifier and system gain, respectively, at 7.12 GHz, and the cascade MMTC Vivaldi-type antenna produced 24 dB of amplifier gain at 8.4 GHz. Also, experiments on a new 2-D H-plane parallel-plate closed system with a stripline slot antenna is introduced, and the wavebeam-mode theory is presented. The new system minimizes scattering and isolation losses associated with open structures. The amplifier gain of the closed system based on slot antennas is compared to the open system based on Vivaldi antennas.}, number={6}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Hicks, CW and Hwang, HS and Steer, MB and Mink, JW and Harvey, JF}, year={1998}, month={Jun}, pages={784–791} }
@article{nuteson_hwang_steer_naishadham_harvey_mink_1997, title={Analysis of finite grid structures with lenses in quasi-optical systems}, volume={45}, ISSN={["0018-9480"]}, DOI={10.1109/22.575583}, abstractNote={A full-wave moment-method technique developed for the analysts of quasi-optical (QO) systems is used to model finite grid structures in a lens system. This technique incorporates an electric-field dyadic Green's function for a grid centered between two lenses. This is derived by separately considering paraxial and nonparaxial fields. Results for the driving point reflection coefficient of a 3/spl times/3 and 5/spl times/5 grid in the lens system are computed and compared with measurements.}, number={5}, journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES}, author={Nuteson, TW and Hwang, HS and Steer, MB and Naishadham, K and Harvey, J and Mink, JW}, year={1997}, month={May}, pages={666–672} }
@inproceedings{feng_fathelbab_lam_haridasan_maria_kingon_steer, title={A 6.2-7.5 GHz tunable bandpass filter with integrated barium strontium titanate (BST) interdigitated varactors utilizing silver/copper metallization}, booktitle={Rws: 2009 ieee radio and wireless symposium}, author={Feng, Z. P. and Fathelbab, W. M. and Lam, P. G. and Haridasan, V. and Maria, J. and Kingon, A. I. and Steer, M. B.}, pages={607–610} }
@article{liu_virdee_inal_steer, title={Microfabrication of conical microfunnels for drug delivery applications}, volume={10}, number={7}, journal={Micro & Nano Letters}, author={Liu, L. W. Y. and Virdee, B. S. and Inal, J. and Steer, M. B.}, pages={355–357} }
@inbook{steer_mink_hwang, title={Planar quasi-optical power combining}, booktitle={Active and quasi-optical arrays for solid-state power combining.}, publisher={New York: Wiley}, author={Steer, M. B. and Mink, J. W. and Hwang, H. S.}, editor={R. A. York and Popovic, Z. B.Editors}, pages={277–292} }
@article{yelten_franzon_steer, title={Surrogate-model-based analysis of analog circuits-part I: Variability analysis}, volume={11}, number={3}, journal={IEEE Transactions on Device and Materials Reliability}, author={Yelten, M. B. and Franzon, P. D. and Steer, M. B.}, pages={466–473} }
@article{yelten_franzon_steer, title={Surrogate-model-based analysis of analog circuits-part II: Reliability analysis}, volume={11}, number={3}, journal={IEEE Transactions on Device and Materials Reliability}, author={Yelten, M. B. and Franzon, P. D. and Steer, M. B.}, pages={458–465} }