Wideband Tunable Bandpass Frequency Selective Surface with Compact Size

A wideband tunable bandpass frequency selective surface with compact size is proposed in this paper. The proposed tunable FSS is composed of three layers with an entire size of 3.6mm×3.6mm×1.02mm.The upper and the bottom layer are identical in construction and there are four varactors loaded on each layer. The metal via which connects the three layers and the rectangular rings on the top and bottom layer provide the bias for the varactors. By applying different voltages to the varactor diode from 0V to 16V, the capacitance of the varactor changes from 0.12pF to 1pF and the center frequency of the FSS varies from 6.1GHz to 16.4GHz. The angular stability of the proposed FSS is also studied. As shown from the simulation results, when the angle of the incident wave changes from 0° to 60°, the presented FSS exhibits a good working performance under different bias voltages.