Microwave Power Limiter Having H-Shaped Slot Structure With Enhanced Plasma Discharge by Electrostatic Potential

A microwave power limiter with an H-type slot structure is proposed as a waveguide structure that blocks high-power microwaves through plasma discharge. At an operating frequency of 5.75 GHz, the electric field is concentrated in the discharging electrode gap; when high power is applied, the plasma limiter discharges, and low power is transmitted. By contrast, when low power is applied, it is transmitted without loss. An H-type resonance structure was used to increase the electric field concentration and selectivity within the waveguide. At 5.75 GHz, the insertion loss of the H-type slot structure was 1.85 dB. The electric field concentration increased to 49492 V/m, and the 3 dB bandwidth was 535 MHz. In addition, the plasma discharge onset level in the xenon gas was lower because of the electrostatic potential. When an electrostatic potential of 300 V was applied, the plasma discharge onset level decreased from 310 to 180 W.