Electromagnetically Induced Transparency Based Metamaterials Integrated with Plasma Cells for High Power Microwave Protection

A simple topology based on electromagnetically induced transparency is introduced for high power microwave protection. Two split ring resonators are placed side by side in such a way that split regions of the SRRs are mutually orthogonal to each other. When a linearly polarized wave made incident to the unit cell, both of the resonator interacts with the incident field in such a way that a transparent window is introduced around 3 GHz providing a window for communication at low power incident waves. Gas discharge tubes are introduced at the split gap region of the SRRs act as plasma cells under high incident power eliminating the transparent window and thus providing protection against high power microwaves. The numerically and experimental results of the proposed limiter are in complete agreement with an insertion loss of 0.4 dB at 3 GHz while isolation goes as high as 30 dB which further increases with the incident power. The power threshold can be easily tuned using DC biasing of the plasma cells and adjusted as desired. Moreover, the device can be easily made frequency reconfigureable by using tunable capacitive elements.