Microwave Corona Breakdown in Coaxial Impedance Transformer: A Theoretical and Experimental Study

We addressed the corona discharge induced by ionization microwave breakdown, a major problem limiting the power of space-borne, coaxial microwave components.The influence of the pressure (in 250~600 Pa range) and temperature on corona-discharge behavior in S-band coaxial impedance transformer was mathematically modeled, theoretically analyzed and experimentally investigated with the lab-built test platform.The calculated results show that resembling Paschen discharge, the corona discharge significantly depends on the pressure, temperature and localized field enhancement.The temperature rise of the involved gases, originated from microwave heating, lowers the critical pressure of ionization microwave breakdown; and a localized field enhancement of microwave strongly decreases the breakdown power-threshold.We suggest that the results be of some technological interest in prediction and prevention of microwave corona-breakdown of coaxial components.