Design of a triple band notched polarization independent compact FSS at UWB frequency range

Abstract

The design of a compact triple band notched Frequency Selective surface (FSS) at Ultra-Wide-Band (UWB) frequency range is presented. To make the proposed FSS polarization insensitive, on the upper part of the substrate a single metallic square loop (SL) and four identical rotational symmetric square split ring resonators (SSRR1) are placed, whereas at the bottom part another four identical rotational symmetric SSRR loops (SSRR2) are printed. Here each SSRR is rotated in 90°clockwise direction over a single layered FR4 substrate. Triple band notches are obtained at WiMAX and Satellite communication downlink C-band (3.3-4.2 GHz), WLAN (5.1-5.9 GHz) and Satellite communication X-band (7.2-8.4 GHz) for both TE and TM polarizations. Angular stability is achieved until 70° and attenuation of more than 25 dB is observed at resonance. The passband is obtained at 4.37 and 6.22 GHz. The proposed structure separates the closely spaced frequency bands by a ratio of 1.44 and 1.39 at the stop band and 1.42 at the pass band. The dimensions of the proposed FSS unit cell are 0.13λ0 × 0.13λ0 × 0.020 λ0, where λ0 represents the free space wavelength at the lowest resonance frequency. Good agreement between modeled and measured results is obtained.