Ultra-Wideband Active Frequency Selective Surface With Wideband Rejection Characteristic

This paper proposes a reconfigurable low-frequency ultra-wideband frequency selective surface in the form of a multilayer cascaded structure to improve out-of-band rejection characteristics. The structure comprises of five FSS layers, with a PIN diode loaded on the top layer to control its operating mode. When the PIN diode is turned OFF, the structure functions as a bandpass filter, achieving a 76.76% -3dB passband bandwidth within the range of 1.14-2.56 GHz. When the PIN diode is turned ON, the structure acts as an ultra-wideband electromagnetic shield with -10dB within the range of 0-20 GHz. It exhibits a stable frequency response for both TE and TM polarization, making it polarization insensitive. The structure can efficiently filter and shield in the 45 degrees oblique incidence range.