Shielding effectiveness of low temperature plasma screen

Plasma has been known to absorb microwave if the microwave frequency is near the characteristic plasma frequency, however, to achieve large area plasma screen with low power is difficult. In this experiment, individual low temperature plasma tubes are arranged into a planar array and microwave transmission attenuation through this array were measured with power input to the plasma tubes as a reference parameter. We found attenuation of ~2 dB at 700 W of input power is achievable on S band signals. Higher attenuation is possible provided the plasma is stable. Higher frequency is also possible if the gap between the plasma tubes can be narrowed.