Investigating the impact metamaterials have on breakdown delay in plasma formation in high power microwave experiments

The efficacy of protecting electronics from high power microwaves (HPM) through plasma creation depends on how quickly the plasma forms in the protective gas chamber when illuminated with microwave radiation. A cylindrical chamber with polycarbonate windows was filled with a neon, krypton gas mixture and illuminated with a train of ~25kW, 800ns long pulses at 43Hz repetition rate as a simulation of the HPM attack scenario. In order to facilitate the formation of a plasma, a set of metamaterial, stainless steel masks for the incident polycarbonate window were created to increase the effective electric field. In addition to the masks, we investigated the effect chamber pressure had on the breakdown delay.