Plasma Based Absorptive and Adaptive High-Power Waveguide Protector

A plasma based adaptive waveguide high-power microwave (HPM) protector is presented in this paper. The proposed structure is comprised of double layer structure with metallic slots perburated and separated by
$0.15\lambda_{0}$
. The coupling effect between the two layers realized a selective broadband frequency protector. The structure posses absorptive and adoptive behaviour with effect of absorptive top layer and plasma on both layers. A prototype is designed for the rectangular waveguide WR-240 and full-wave simulation along with experimental verification proves the working mechanism. The results shows an insertion loss 1.5 dB in the whole working band with relative bandwidth 6% during low power incoming signals. Once the incident signal power exceeds the protection threshold of the protector, signal can be attenuated by more than 30 dB. The out-of transmission band has absorption below 10 dB in S-band region.