Numerical Analysis of Ultrathin and Polarization-Insensitive FSS with Wide-Stopband and Dual-Passband Response for Conformal Applications

A novel, ultrathin frequency-selective surface (FSS) has been developed and fine-tuned for EM shielding within the C-band, X-band, and initial frequencies of Ku-band. The design comprises a crossed double-sided arrow confined in a square aperture with a centered circular void. This FSS design offers a broader 3-dB bandwidth response of 5.39 GHz, effectively covering frequencies ranging from 5.85 GHz to 11.25 GHz. It focuses on a central frequency of 7.93 GHz, delivering a shielding effectiveness (SE) of 41.8 dB. In addition, the proposed FSS offers dual passband response centering at 4.78 GHz and 13.215 GHz. The thickness of the proposed FSS is less than λ
0
⁄150 , where λ
0
is the lowest operating wavelength. The symmetric structure of the proposed wide-stopband FSS design imparts polarization-insensitive characteristics, ensuring a stable response at normal and oblique incidences for both TE and TM modes. Furthermore, the presented FSS design is analyzed for inbound and outbound bending making it suitable for conformal applications. Eventually, the numerically simulated results are verified with the outcomes of the equivalent circuit model.