Plasma-discharge-integrated slot structure for microwave power limiter

A slot structure was combined with a discharge electrode to limit incident high-power microwaves via the integration of plasma discharge. At the target resonating frequency of 9.45 GHz, the surface current was concentrated at an electrode, and the electric field was enhanced by the proposed design to lower the response power level of the incident signal. When a low-power signal is injected, plasma is not generated, and the incident wave travels without insertion loss. Double-stage slot structures were utilized to broaden the band-pass characteristics in the frequency domain, and the demonstrated plasma limiter exhibited an insertion loss of 1.01 dB at 9.45 GHz. The xenon gas pressure was optimized with the shortest distance of 100 µm between the upper and lower electrodes to reduce the discharge power of the plasma. In the case of a high-power signal input, as xenon-gas breakdown occurred, the transmitted signal was close to zero, and most of the high-power signal was reflected with a blocking efficiency of 40.55 dB. The demonstrated result will be useful to protect the receiver of a radio detection and ranging system from the high power microwave.