A Low-Profile Frequency Selective Surface With Controllable Triband Characteristics

A novel compact low-profile frequency selective surface (FSS) with controllable triband characteristics is presented. The proposed FSS consists of a stacked periodic array of square loops and complementary apertures, respectively centered within a wire grid and an aperture grid, which can create three transmission poles and two transmission zeros. Controllable triband performance is achieved, allowing the FSS to transmit the signal at 4 GHz while reflecting the signals at 6 and 9.5 GHz. Due to the compact and low-profile structure, the designed FSS has a reduced sensitivity to the incident angle compared to traditional triband FSSs. An equivalent circuit model is proposed for predicting and analyzing the frequency characteristics of this structure. For demonstration, a prototype of the proposed FSS is fabricated and measured. Good agreement between the simulated and measured results is observed.