Plasma-tunable electronic protection for microwave applications

The feasibility of practical reconfigurable electromagnetic shielding system is investigated. The proposed design is a low profile frequency selective surface (FSS) integrated with compact plasma-shells. Reconfigurability is achieved by energizing the shells thus altering the transfer function of the FSS from transmission mode to protection mode. This mechanism is due to the formation of plasma which becomes lossy conductive and acts as electric wall against electromagnetic (EM) waves. A prototype operating at S-band has been fabricated and tested inside a waveguide. Measurements reveal that the platform is transparent to the electromagnetic wave within the operating band at OFF state. While at ON state, fast in-band switching capability in the order of 10-100 ns with the ability to suppress about 60 dB in-band EM field intensity is achieved. Reconfigurable electromagnetic shielding systems based on plasma-shells may be particularly useful when subject to high power microwave energy (HPME) and high electromagnetic pulse (HEMP).