@article{hayes_desai_liu_annamaa_lazzi_dickey_2014, title={Microfluidic coaxial transmission line and phase shifter}, volume={56}, ISSN={["1098-2760"]}, DOI={10.1002/mop.28327}, abstractNote={ABSTRACTThis article presents a microfluidic coaxial transmission line assembly that is realized by weaving together stretchable metallic fibers composed of a liquid‐metal core inside an elastomeric shell. These fibers are woven around a core fiber to create a coaxial assembly. The resulting structure exhibits exceptional stretchability compared to conventional coaxial transmission lines. The mechanical properties of the supporting elastomer and the fluidic properties of the conductors ensure that the characteristic impedance of the transmission line is maintained while stretched. As a result, the system is well suited for applications requiring durable transmission lines and tunable phase shifters (or time‐delay lines). A prototype fluidic coaxial structure is characterized that consists of eutectic gallium indium (EGaIn) encased in an elastomeric poly‐styrene‐(ethylene‐co‐butylene)‐styrene (SEBS). © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1459–1462, 2014}, number={6}, journal={MICROWAVE AND OPTICAL TECHNOLOGY LETTERS}, publisher={Wiley}, author={Hayes, Gerard J. and Desai, Sharvil C. and Liu, Yuyu and Annamaa, Petteri and Lazzi, Gianluca and Dickey, Michael D.}, year={2014}, month={Jun}, pages={1459–1462} }
 @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_liu_genzer_lazzi_dickey_2014, title={Self-Folding Origami Microstrip Antennas}, volume={62}, ISSN={["1558-2221"]}, DOI={10.1109/tap.2014.2346188}, abstractNote={This communication presents antennas that incorporate self-folding polymer substrates that transform planar, two-dimensional structures into three-dimensional antennas when exposed to a light source. Pre-strained polystyrene sheets supporting a patterned copper foil form the light-activated structures. Black ink that is inkjet printed on the polymer substrate selectively absorbs light and controls the shape of the transformation. This approach represents a simple method to reconfigure the shape of an antenna and a hands-free method to assemble 3D antennas from many of the conventional methods that are used to pattern 2D metal foils. We demonstrate and characterize two embodiments that highlight this concept: a monopole antenna that transforms from a conventional microstrip transmission line and a microstrip patch antenna that converts within seconds into a monopole antenna.}, number={10}, journal={IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Hayes, Gerard J. and Liu, Ying and Genzer, Jan and Lazzi, Gianluca and Dickey, Michael D.}, year={2014}, month={Oct}, pages={5416–5419} }
 @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{cumby_hayes_dickey_justice_tabor_heikenfeld_2012, title={Reconfigurable liquid metal circuits by Laplace pressure shaping}, volume={101}, ISSN={["1077-3118"]}, DOI={10.1063/1.4764020}, abstractNote={We report reconfigurable circuits formed by liquid metal shaping with <10 pounds per square inch (psi) Laplace and vacuum pressures. Laplace pressure drives liquid metals into microreplicated trenches, and upon release of vacuum, the liquid metal dewets into droplets that are compacted to 10–100× less area than when in the channel. Experimental validation includes measurements of actuation speeds exceeding 30 cm/s, simple erasable resistive networks, and switchable 4.5 GHz antennas. Such capability may be of value for next generation of simple electronic switches, tunable antennas, adaptive reflectors, and switchable metamaterials.}, number={17}, journal={APPLIED PHYSICS LETTERS}, publisher={AIP Publishing}, author={Cumby, Brad L. and Hayes, Gerard J. and Dickey, Michael D. and Justice, Ryan S. and Tabor, Christopher E. and Heikenfeld, Jason C.}, year={2012}, month={Oct} }
 @article{khan_hayes_so_lazzi_dickey_2011, title={A frequency shifting liquid metal antenna with pressure responsiveness}, volume={99}, ISSN={["0003-6951"]}, DOI={10.1063/1.3603961}, abstractNote={This letter describes the fabrication and characterization of a shape shifting antenna that changes electrical length and therefore, frequency, in a controlled and rapid response to pressure. The antenna is composed of a liquid metal alloy (eutectic gallium indium) injected into microfluidic channels that feature rows of posts that separate adjacent segments of the metal. The initial shape of the antenna is stabilized mechanically by a thin oxide skin that forms on the liquid metal. Rupturing the skin merges distinct segments of the metal, which rapidly changes the length, and therefore frequency, of the antenna. A high speed camera elucidates the mechanism of merging and simulations model accurately the spectral properties of the antennas.}, number={1}, journal={APPLIED PHYSICS LETTERS}, publisher={AIP Publishing}, author={Khan, Mohammad Rashed and Hayes, Gerard J. and So, Ju-Hee and Lazzi, Gianluca and Dickey, Michael D.}, year={2011}, month={Jul} }