An EVA-Based High-Power and Absorptive Frequency-Selective Plasma Limiter

A novel frequency-selective limiter (FSL) topology is proposed to protect receiver front-ends against high-power microwaves. The design incorporates plasma cells embedded within cylindrical cavities to generate evanescent modes in a two-pole absorptive filter topology. The FSL transitions from an all-pass to a highly selective bandstop mode when the input power surpasses the gas breakdown threshold in one of the plasma cells. This transition is due to a shift from constructive to destructive interference between the two signal paths, caused by the reversal of magnetic field polarity in the inter-resonator coupling. The theory of this novel plasma FSL is developed and comprehensively evaluated. The fabricated C-band prototype achieves less than 2.4 dB insertion loss, over 60 dB isolation, a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$10-\text{dB}$</tex> fractional bandwidth of 2.9 %, and power handling exceeding 100 W.