Toward a High-Power High-Isolation Wideband Plasma Limiter

A novel circuit design for a wideband high-power limiter is presented. A two-stage topology is utilized to cascade a coplanar waveguide transmission line symmetrically loaded with shunt gas discharge tubes (self-contained plasma cell devices) and a commercial RF MEMS switch. An initial-stage integration of the design is fabricated and measured, and test results are presented. A maximum insertion loss of 0.5 dB, a return loss better than 14.5 dB, and a limiting isolation greater than 24 dB are measured over a 1-3 GHz frequency bandwidth. Relaxation and response time measurements are on the order of microseconds. The direction of further developments to the proposed design is also discussed.