A Miniaturized Angularly Stable FSS for Shielding GSM 0.9, 1.8, and Wi-Fi 2.4 GHz Bands

Abstract

A triband band-stop spatial filter shield using frequency selective surface is designed and analyzed to block GSM 900, 1800, and Wi-Fi 2400 MHz frequency bands. Three constituent resonant elements exhibiting stop-bands are two Jerusalem cross (JC) elements with tortuous main arms, and a 45° rotated JC. The proposed unitcell is compact with size 0.078λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> x 0.078λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength of lowest resonant frequency in free space. An equivalent circuit model is developed to understand the behavior of its constituent elements. The proposed design offers better miniaturization and stable frequency response for up to 60° of incidence angle for both TE and TM polarizations, as compared to the earlier reported designs in the bands mentioned previously. Shielding effectiveness is verified with measurements in an anechoic chamber.