Development of Large-Area Switchable Plasma Device for X-Band Applications

Abstract

This paper demonstrates a large-area, lightweight, conformal plasma device that interacts with propagating X-band microwave energy. The active elements are rugged plasma-shells - hollow ceramic shells encapsulating a controlled-pressure gas that can be ionized to controlled plasma parameters. Plasma-shells are electrically excited by frequency selective surfaces that are transparent to the frequency band of interest. The result is equivalent to large-area free-space plasma confined in a discrete plasma slab. A novel structure is designed with the aid of full-wave simulation and fabricated as a 76.2-mm square array, and transmission performance is tested across different drive voltages and angles of incidence. Switchable attenuation of 7 dB is measured across the passband when driven with 1400 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pp</sub> at 1 MHz. Plasma parameters are estimated from theory and full-wave simulation, with electron density estimated to be 3.6×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> . The proposed structure has potential for use on mobile platforms.