A Dual-Polarized Quasi-Elliptical Frequency Selective Surface With Ultrawide Passband and Sharp Roll-Off

This paper proposes a high-performance frequency selective surfaces (FSS), achieving an optimal balance of passband width, roll-off rate, angular stability and fabrication simplicity. A novel equivalent circuit model is first designed, featuring an improved circuit structure that optimizes resonator arrangement to achieve a wide passband and sharp roll-off. A dual-polarized FSS is then designed using differentiated capacitive patches and a modified Jerusalem cross composite structure, which is derived from the proposed circuit model. The simulated FSS achieves a -3 dB wide passband from 2.48 GHz to 6.81 GHz (93.2%). The roll-off rates on both sides of the passband reach 27.27 dB/GHz and 35.29 dB/GHz, respectively. Finally, a fabricated prototype confirms strong agreement with simulations. This work introduces a circuit-based FSS design with excellent passband width, low insertion loss, fast roll-off, high angle stability and easy fabrication, making it highly suitable for wideband antenna systems, and electromagnetic shielding applications.