Design and Analysis of Single Sided Modified Square Loop UWB Frequency Selective Surface

Abstract

In this article, a compact frequency selective surface (FSS) is implemented using a modified metallic square loop structure for ultrawide band (UWB) stop behavior. The proposed structure exhibits wideband rejection over the entire UWB, ranging from 3.1 to 10.8 GHz. The proposed structure manifests polarization independent characteristics and provides a stable frequency response for normal and oblique angles under both transverse electric (TE) and transverse magnetic (TM) incident polarization. The angular stability for various polarization angles is also obtained. This structure provides a −10dB wide impedance bandwidth of 110.79%. The maximum relative deviation in between transmission zero frequency and angularly incident frequency is 5.9% and 6.2% at 80˚ TE and TM polarized wave, respectively, with attenuation more than 45 dB. The unit cell of the proposed FSS is imprinted on single-layer FR4 substrate of the dimensions 6 × 6 mm2, which is 0.062× 0.062 λ, where λ is the wavelength of lower cut-off frequency and is by far the smallest design for the desired UWB rejection FSS.