Compact Single Resonator Dual-Bandstop FSS Filter with Wider Angular Stability for S, and X-Bands

This paper proposes a novel dual-bandstop frequency selective surface (FSS) designed to operate in the S and X bands. It functions as a bandstop filter at 2.37 GHz and 8.01 GHz. The proposed structure exhibits significant polarization insensitivity, ensuring uniform frequency performance for TE and TM polarizations. A significant advantage is angular stability, maintaining its filtering properties for incidence angles up to 60° in both polarizations. The structure’s resonance behavior is examined using a surface current analysis. The unit cell is exceptionally compact, covering an area of around 0.12 λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> × 0.12 λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf>, where λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> represents the free-space wavelength.