Investigating failure mechanisms in high-power microwave frequency selective surfaces

When operated in high-power pulsed systems, frequency selective surfaces (FSS) are susceptible to breakdown. Breakdown in these devices changes the frequency response of the device and can result in permanent damage in certain situations. Recently, it has been demonstrated that breakdown induced at a certain location in an FSS can result in breakdown at other locations (e.g. neighboring unit cells) where the intensity of the incident EM wave is not high enough to cause breakdown under normal circumstances. In this paper, we examine the physical cause of this phenomenon and demonstrate that this is caused by the generation of vacuum ultraviolet (VUV) radiation, at the location of the initial discharge, which facilitates breakdown at other locations. Furthermore, through a series of experimental studies, we identify the distances over which this VUV radiation has a high enough intensity to facilitate breakdown at the neighboring unit cells. The results presented in this paper are expected to be useful in mitigating and localizing the adverse impacts of breakdown in HPM FSSs covering large aperture dimensions or in designing devices that generate large scale breakdown (e.g. periodic plasmas).