Plasma-Tunable Double-Bandpass Frequency Selective Surface

Herein, a tunable frequency selective surface (FSS) based on the regulation capacity of plasma in the X-band is presented. The proposed FSS is composed of a bi-layer resonant element separated by trapped plasma in quartz. The design exhibits two bandpasses with center frequencies at 9.542GHz and 11.124GHz when the plasma is not excited. When the plasma is excited, the two bandpasses with center frequencies shift to a higher regime as the plasma frequency increases; however, the bandwidth decreases, and the optimal insertion loss of bandpass can reach -0.35dB.