A Dual-Band Dual-Polarization Frequency Selective Surface With Wide-Range Flexible Band Ratio and Wide Angular Stability

A dual-band dual-polarization frequency selective surface (FSS) with wide-range flexible band ratio and wide angular stability is proposed. Subwavelength metal walls acted as plate capacitors are loaded onto two separate radiating square slot elements arranged in a triangular array to realize miniaturization and wide-range flexible band ratio from 1.33 to 7.11 in 1–7.7 GHz. The single-layer square slot resonator is modified into a two-layer self-decoupling structure with reverse currents in different layers to realize wide angular stability up to 70
$^{\circ}$
. Based on the substrate integrated waveguide (SIW) theory, the metal walls can be represented by arrays of vias for fabrication. The independently controllable passband responses and equivalent circuit model (ECM) significantly simplify the FSS design. A prototype of the proposed FSS has been fabricated and measured. The measured results have favorable agreement with the simulated results, thus validating the FSS design. The proposed FSS can act as antenna radome and antenna decoupling structure, which can be widely used in multiband antennas, shared-aperture antennas, wide-angle scanning antenna arrays, and near-field loading, with high design flexibility.