Design Methodology of Dual-Polarized Angle-Selective Surface Based on Three-Layer Frequency-Selective Surfaces

This article presents the design methodology of dual-polarized angle-selective surface (ASS) based on three-layer frequency-selective surface (FSS). The entire structure is analyzed with an equivalent circuit model, and the corresponding bandpass condition in terms of the FSS's normalized susceptance is first derived. The wideband and stopband conditions are also derived analytically, and a general design methodology is proposed to realize an ASS of wideband, high angular selectivity, and dual-polarization operation. To verify the proposed design methodology, a low-pass ASS example based on the complementary Swastika-shaped resonance is proposed. Simulation results show that the proposed ASS achieves 5% bandwidth (from 2.94 to 3.1 GHz) with a passband ( S_21 > -1 dB) from 0° to 15° and a stopband ( S_21 < -20 dB) from 30°. The proposed ASS is then above a high-gain horn antenna, and it can effectively suppress the horn antenna's sidelobes. A prototype of the proposed ASS is fabricated, and measured results agree well with the simulated ones.