Characteristics of Microwave Breakdown in Cavity Filter under High Power Microwave Environment

Cavity filter is widely used in microwave receiver front-end subsystem for the advantage of its low insertion loss, excellent band selectivity, and relative high power handle characteristics. However, the short high power microwave pulse transmission response in cavity filter is seldom studied, especially under high power microwave (HPM) electromagnetic environment. By the Particle-In-Cell/Monte Carlo Collision simulation and high power tests, the transient microwave breakdown phenomenon of an S band comb-line cavity filter are discussed. The simulation and test results show that when the input microwave pulse width is 50ns, the microwave breakdown power threshold value is about 500W. And the filter output would be nearly suppressed while the input power above 3.5kW. The simulation data of different microwave pulse widths demonstrate that the breakdown power threshold is approximately inversely proportional to the microwave pulse width in case of the pulse width is lower than 100ns.