Microwave breakdown in waveguide filters, numerical simulation, and comparison to experiments

Abstract : Microwave breakdowns in output multiplexer filters, boarded on telecommunications satellites, can affect the device and damage it. During tests at atmospheric pressure, these breakdowns are generally initiated in the vicinity of a noble metal coated frequency adjustment screw. A modeling of the microwave breakdown ignition is developed taking into account the thermoelectronic emission from the screw and the noble metal atom vaporization. The influence of field strength is particularly investigated to predict the breakdown delay after the application of the microwave power. Then, a specific structure has been designed and built and a dedicated measurement procedure has been proposed. As it will be shown, the test structure experimental behavior agrees well with the theoretical one. Finally, the results given by the numerical modeling of microwave breakdown are compared to the measurements performed in a five-pole filter of an output multiplexer