@article{qusba_ramrakhyani_so_hayes_dickey_lazzi_2014, title={On the Design of Microfluidic Implant Coil for Flexible Telemetry System}, volume={14}, ISSN={["1558-1748"]}, DOI={10.1109/jsen.2013.2293096}, abstractNote={This paper describes the realization of a soft, flexible, coil fabricated by means of a liquid metal alloy encased in a biocompatible elastomeric substrate for operation in a telemetry system, primarily for application to biomedical implantable devices. Fluidic conductors are in fact well suited for applications that require significant flexibility as well as conformable and stretchable devices, such as implantable coils for wireless telemetry. A coil with high conductivity, and therefore low losses and high unloaded Q factor, is required to realize an efficient wireless telemetry system. Unfortunately, the conductivity of the liquid metal alloy considered-eutectic gallium indium (EGaIn)-is approximately one order of magnitude lower than gold or copper. The goal of this paper is to demonstrate that despite the lower conductivity of liquid metal alloys, such as EGaIn, compared with materials, such as copper or gold, it is still possible to realize an efficient biomedical telemetry system employing liquid metal coils on the implant side. A wireless telemetry system for an artificial retina to restore partial vision to the blind is used as a testbed for the proposed liquid metal coils. Simulated and measured results show that power transfer efficiency of 43% and 21% are obtained at operating distances between coils of 5 and 12 mm, respectively. Further, liquid metal based coil retains more than 72% of its performance (voltage gain, resonance bandwidth, and power transfer efficiency) when physically deformed over a curved surface, such as the surface of the human eye. This paper demonstrates that liquid metal-based coils for biomedical implant provide an alternative to stiff and uncomfortable traditional coils used in biomedical implants.}, number={4}, journal={IEEE SENSORS JOURNAL}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Qusba, Amit and RamRakhyani, Anil Kumar and So, Ju-Hee and Hayes, Gerard J. and Dickey, Michael D. and Lazzi, Gianluca}, year={2014}, month={Apr}, pages={1074–1080} }
 @article{hayes_so_qusba_dickey_lazzi_2012, title={Flexible Liquid Metal Alloy (EGaIn) Microstrip Patch Antenna}, volume={60}, ISSN={["0018-926X"]}, DOI={10.1109/tap.2012.2189698}, abstractNote={This paper describes a flexible microstrip patch antenna that incorporates a novel multi-layer construction consisting of a liquid metal (eutectic gallium indium) encased in an elastomer. The combined properties of the fluid and the elastomeric substrate result in a flexible and durable antenna that is well suited for conformal antenna applications. Injecting the metal into microfluidic channels provides a simple way to define the shape of the liquid, which is stabilized mechanically by a thin oxide skin that forms spontaneously on its surface. This approach has proven sufficient for forming simple, single layer antenna geometries, such as dipoles. More complex fluidic antennas, particularly those featuring large, co-planar sheet-like geometries, require additional design considerations to achieve the desired shape of the metal. Here, a multi-layer patch antenna is fabricated using specially designed serpentine channels that take advantage of the unique rheological properties of the liquid metal alloy. The flexibility of the resulting antennas is demonstrated and the antenna parameters are characterized through simulation and measurement in both the relaxed and flexed states.}, number={5}, journal={IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Hayes, Gerard J. and So, Ju-Hee and Qusba, Amit and Dickey, Michael D. and Lazzi, Gianluca}, year={2012}, month={May}, pages={2151–2156} }
 @article{so_thelen_qusba_hayes_lazzi_dickey_2009, title={Reversibly Deformable and Mechanically Tunable Fluidic Antennas}, volume={19}, ISSN={["1616-3028"]}, DOI={10.1002/adfm.200900604}, abstractNote={This paper describes the fabrication and characterization of fluidic dipole antennas that are reconfigurable, reversibly deformable, and mechanically tunable. The antennas consist of a fluid metal alloy injected into microfluidic channels comprising a silicone elastomer. By employing soft lithographic, rapid prototyping methods, the fluidic antennas are easier to fabricate than conventional copper antennas. The fluidic dipole radiates with ≈90% efficiency over a broad frequency range (1910–1990 MHz), which is equivalent to the expected efficiency for a similar dipole with solid metallic elements such as copper. The metal, eutectic gallium indium (EGaIn), is a low‐viscosity liquid at room temperature and possesses a thin oxide skin that provides mechanical stability to the fluid within the elastomeric channels. Because the conductive element of the antenna is a fluid, the mechanical properties and shape of the antenna are defined by the elastomeric channels, which are composed of polydimethylsiloxane (PDMS). The antennas can withstand mechanical deformation (stretching, bending, rolling, and twisting) and return to their original state after removal of an applied stress. The ability of the fluid metal to flow during deformation of the PDMS ensures electrical continuity. The shape and thus, the function of the antenna, is reconfigurable. The resonant frequency can be tuned mechanically by elongating the antenna via stretching without any hysteresis during strain relaxation, and the measured resonant frequency as a function of strain shows excellent agreement (±0.1–0.3% error) with that predicted by theoretical finite element modeling. The antennas are therefore sensors of strain. The fluid metal also facilitates self‐healing in response to sharp cuts through the antenna.}, number={22}, journal={ADVANCED FUNCTIONAL MATERIALS}, publisher={Wiley}, author={So, Ju-Hee and Thelen, Jacob and Qusba, Amit and Hayes, Gerard J. and Lazzi, Gianluca and Dickey, Michael D.}, year={2009}, month={Nov}, pages={3632–3637} }
 @article{singh_qusba_roy_castro_mcclure_dai_greenberg_weiland_humayun_lazzi_2009, title={Specific Absorption Rate and Current Densities in the Human Eye and Head Induced by the Telemetry Link of an Epiretinal Prosthesis}, volume={57}, ISSN={["1558-2221"]}, DOI={10.1109/TAP.2009.2028498}, abstractNote={The fields induced in the human head by the wireless telemetry used for Second Sight Medical Product, Inc.'s epiretinal prosthesis system are characterized for compliance testing with international safety standards using a three-dimensional (3-D) finite-difference time-domain (FDTD) code in D-H formulation. The specific system under consideration utilizes an inductive link with a primary coil mounted on the subject's eyeglasses and a secondary coil that is strapped on the eye, over the sclera. The specific absorption rate (SAR) and the current density have been obtained computationally for different relative positions of the primary and secondary coils to account for the relative misalignment of the two due to the movement of the eye with the implant. For a peak normalized current of 0.62 A in the primary coil at 10 MHz, the highest peak 1-g SAR was found to be 0.45 W/Kg, and the maximum root mean square (rms) current density averaged over a 1-cm2 area was found to be 16.05 A/m2, both of which are within the limits imposed by IEEE and ICNIRP safety standards. Simulations between 2 and 20 MHz indicated that the induced electric field values scale well with frequency, thus providing guidelines for the determination of the final frequency and input power requirements of operation for the telemetry system to meet safety standards.}, number={10}, journal={IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, author={Singh, Vinit and Qusba, Amit and Roy, Arup and Castro, Richard A. and McClure, Kelly and Dai, Rongching and Greenberg, Robert J. and Weiland, James D. and Humayun, Mark S. and Lazzi, Gianluca}, year={2009}, month={Oct}, pages={3110–3118} }
 @inproceedings{lazzi_qusba_singh_2008, title={On the design of telemetry coils and implantable small antennas for a retinal prosthesis to restore partial vision to the blind}, ISBN={978-1-4244-2041-4}, booktitle={2008 IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting}, publisher={[Piscataway, NJ]: IEEE}, author={Lazzi, G. and Qusba, A. and Singh, V.}, year={2008}, pages={592–594} }