@article{hari_ellington_floyd_2023, title={A Reflection-Mode N-Path Filter Tunable From 6 to 31 GHz}, volume={1}, ISSN={["1558-173X"]}, DOI={10.1109/JSSC.2023.3235976}, abstractNote={A 6-to-31-GHz reflection-mode $N$ -path filter is implemented in 45-nm SOI technology. The filter includes an on-chip hybrid coupler with through and coupled ports terminated with four-phase passive mixers. Each mixer provides a high impedance in-band and a matched, 50- $\Omega $ impedance out-of-band (OOB) that is provided by the ON-resistance of the switches. As such, in-band signals are reflected by the mixers, and OOB signals are absorbed. This enables reflection-mode bandpass filtering of the signal, with the center frequency set by the local-oscillator frequency. To increase selectivity, an active baseband (BB) load with adjustable bandwidth can be enabled to provide a second-order capacitive response, which increases the roll-off to 12 dB/octave. Measurements show that the filter can be tuned across 6–31 GHz with a maximum 3-dB RF bandwidth of 0.47 GHz for the passive BB and either 0.22 or 1.22 GHz for the active BB in narrowband or wideband modes. Filter insertion loss (IL) is < 7 dB in all three modes, whereas the noise figure exceeds IL by 1 dB at 6 GHz and 11 dB at 29 GHz in the active-wide mode. The filter provides a return loss of < 10 dB both in-band and OOB. In all three modes of the filter, the in-band input-referred third-order intercept point (IIP3) is<−2.2 dBm and the OOB IIP3 is > 11 dBm, whereas the maximum in-band input-referred P1 dB is −2 dBm. Clock circuitry consumes 75–320 mW from 6 to 31 GHz, whereas the active BBs consume 70 mW in the wideband mode and 90 mW in the narrowband mode.}, journal={IEEE JOURNAL OF SOLID-STATE CIRCUITS}, author={Hari, Sandeep and Ellington, Cody J. and Floyd, Brian A.}, year={2023}, month={Jan} }
 @article{ellington_hari_floyd_2023, title={Analysis and Design of Baseband Circuits for Higher-Order Reflection-Mode N-Path Filters}, volume={10}, ISSN={["1558-0806"]}, DOI={10.1109/TCSI.2023.3321872}, abstractNote={A design methodology for the synthesis of baseband circuits for higher-order reflection-mode N-path filters (RMNFs) is presented. Beginning with a linear time-invariant (LTI) model, equations are formulated that provide intuition for the designer with regard to signal and noise transfer through the RMNF. Building upon the mathematical foundation of the LTI model, an interdependence between signal and noise is explored and addressed. Furthermore, two baseband synthesis approaches are presented and connected with other state-of-the-art works. Finally, a 12-18GHz RMNF design with third-order selectivity (18dB/octave) is performed with analytical, simulated, and measured hardware results to validate the presented methodology.}, journal={IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS}, author={Ellington, Cody J. and Hari, Sandeep and Floyd, Brian A.}, year={2023}, month={Oct} }