Broadband Dual-Polarized Angle-Selective Surface Based on Multilayered Frequency-Selective Surfaces

This letter presents a novel design method of broadband, dual-polarized angle-selective surface (ASS) based on multi-layered frequency-selective surfaces. The equivalent circuit model of the multi-layered ASS is constructed and analyzed. To achieve high transmission under the normal incidence and strong reflection under the oblique incidence, the normalized susceptance of each FSS layer is optimized. A low-pass ASS consisting of three distinct FSS patterns, including Swastika-shaped, cross-slot, and double-square grid, is proposed. Simulated results show that the proposed ASS is broadband, realizing 12.2% bandwidth from 4.6 to 5.2 GHz, maintaining a passband (|S21| > −1 dB) across the entire 4.6-5.2 frequency band for incident angles up to 5°, and exhibiting a stopband (|S21| < −10 dB) for incident angles larger than 40°. To verify the design method, a prototype of five-layer ASS sample with 18×18 unit cells is fabricated. Measured results are in excellent agreement with the simulated ones.