Polymer composites with electrically conductive fillers have been developed as mechanically flexible, easily processable electromagnetic interference (EMI) shielding materials. Although there are a few elastomeric composites with nanostructured silvers and carbon nanotubes showing moderate stretchability, their EMI shielding effectiveness (SE) deteriorates consistently with stretching. Here, a highly stretchable polymer composite embedded with a three‐dimensional (3D) liquid‐metal (LM) network exhibiting substantial increases of EMI SE when stretched is reported, which matches the EMI SE of metallic plates over an exceptionally broad frequency range of 2.65–40 GHz. The electrical conductivities achieved in the 3D LM composite are among the state‐of‐the‐art in stretchable conductors under large mechanical deformations. With skin‐like elastic compliance and toughness, the material provides a route to meet the demands for emerging soft and human‐friendly electronics.

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A proof of concept for a microwave microplasma generator that consists of a halved dielectric resonator is presented. The generator functions via leaking electric fields of the resonant modes — TE01δ and HEM12δ modes are explored. Computational results illustrate the electric fields, whereas the stability of resonance and coupling are studied experimentally. Finally, a working device is presented. This generator promises potentially wireless and low-loss operation. This device may find relevance in plasma metamaterials; each resonator may generate the plasma structures necessary to manipulate electromagnetic radiation. In particular, the all-dielectric nature of the generator will allow low-loss interaction with high-frequency (GHz–THz) waves.

Split-ring resonators have been popularized by their application in metamaterials, but their ability to concentrate electric fields has also made them useful as microwave plasma generators. Despite the existence of much work on plasma generation using ring resonators, a comparative study of the effect of different materials on plasma generation performance has been absent. This work focuses on the study of material effects on ring resonators' microwave properties and plasma generation performance at pressures ranging from 4 to 100 Torr. To achieve this end, screen-printed silver and gold ring resonators are studied due to their high conductivity, relatively low reactivity, and differences in conductivity and work function. The surface morphology and chemistry of the ring resonators are studied using optical profilometry, scanning electron microscopy, and X-ray photoelectron spectroscopy. It is found that the main factor influencing performance between these two materials is Q-factor, which is determined using both conventional bandwidth measurements and measurements of conductivity. Q-factor is further isolated by modifying a silver ring resonator such that its Q-factor matches gold ring resonators. In addition, a film formed on the silver resonators after plasma exposure provides an opportunity to study a material, which, unlike gold, is quite different from silver. With the film present, plasma generation performance is decreased with increasing severity as pressure is decreased—20% more power is required for breakdown at 4 Torr. This change is qualitatively consistent with a model of microwave plasma breakdown where boundary effects are expected to increase as pressure is decreased.

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A set of three apparatus enabling RF exposure of aerosolized pathogens at four chosen frequencies (2.8 GHz, 4.0 GHz, 5.6 GHz, and 7.5 GHz) has been designed, simulated, fabricated, and tested. Each apparatus was intended to operate at high power without leakage of RF into the local environment and to be compact enough to fit within biocontainment enclosures required for elevated biosafety levels. Predictions for the range of RF electric field exposure, represented by the complex electric field vector magnitude, that an aerosol stream would be expected to encounter while passing through the apparatus are calculated for each of the chosen operating frequencies.

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Thin and flexible glass ribbons can be rolled into a film capacitor structures for power electronic circuits. Glass has excellent electrical properties and is a leading candidate to replace polymer films for high‐temperature applications. The dielectric properties of a low‐alkali aluminoborosilicate glass were characterized up to temperatures of 400°C. Low‐field permittivity values of 6 with dielectric loss below 0.01 were found for temperatures below 300°C. The dielectric breakdown strength exceeded 5 MV/cm for temperature of 400°C and high‐field polarization measurements showed that glass has over 95% energy efficiency at temperatures of 200°C, which is a target temperature for high‐temperature power electronic circuits driven by wide bandgap semiconductor devices.