An EVA Cavity-Based Frequency-Selective Plasma Limiter

High-power microwaves present a substantial hazard, capable of damaging electrical systems and disrupting their signals. To mitigate these risks, a reconfigurable frequency-selective limiter (FSL) is needed to operate within safe frequency ranges, effectively blocking threats at specific frequencies of high power. Various FSL architectures have been proposed in recent years, employing diodes, thin films, filter-based topologies, and ferrite materials. However, these approaches have limitations such as low power handling, high insertion loss, limited tunability, and suboptimal selectivity. Addressing these challenges, there is a need for an innovative and improved FSL design that overcomes the limitations of existing architectures.

This study presents an innovative Evanescent-mode (EVA) cavity resonator-based frequency-selective limiter that incorporates a gas discharge tube (GDT) within the inter-resonator coupling structure. The device consists of two signal paths: the first path traverses the EVA resonators and GDT, while the second path includes a phase delay line. The limiter exhibits an all-pass response at low input powers due to constructive interference between the signal paths. However, when subjected to high input powers, gas breakdown occurs within the inter-resonator GDT, leading to a phase reversal induced by the plasma's dielectric properties [1]. Consequently, destructive interference between the signals occurs over a narrow frequency band, resulting in a selective band-stop response. Experimental results of the EVA-based plasma FSL will be discussed, showcasing its remarkable attributes, including high power handling capabilities, low insertion loss, fast response time, and notable selectivity performance. The findings of this study highlight the potential of the EVA-based plasma frequency-selective limiter as an effective solution for high-power microwave mitigation, offering enhanced selective protection for sensitive electronic systems.

[1] S.N. Ramesh, A.Semnani, “A Comprehensive Circuit Modeling Approach for Self-Sustained Capacitively Coupled Microwave Plasma” IEEE Transactions on Plasma Science, vol. 49, no. 9, pp. 2690-2699, Sept 2021.