A Simple Multilayer Frequency Selective Surface for Ultra Wide Band Applications

This paper introduces a simple two layered frequency selective surface (FSS) designed in a way to operate over ultra-wide band (UWB) frequency range. A broadband FSS as ‘reflector’ is designed by introducing identical periodic structures on both sides of substrate. The FSS is designed to behave as a reflector (i.e. reflection coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{S}_{11}/\mathrm{S}_{22} \sim 0 \text{dB}$</tex> and transmission coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{S}_{12}/\mathrm{S}_{21} \leq-10 \text{dB}$</tex>), with unit cell dimensions <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.26 \lambda_{o} \times 0.26 \lambda_{o} \times 0.026 \lambda_{o}$</tex>, where <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda_{o}$</tex> is the wavelength corresponding to the mid of the operating frequency band i.e., from 4.7 GHz to 10.9 GHz. Further, the proposed FSS is checked for angular and polarization stabilities. The proposed FSS gives angular stability over its operating range for incident angles up to 45° and also provides stable responses for different polarization angles. Next, the working mechanism of the proposed FSS structure is made more understandable by providing the transmission line equivalent circuit model. The FSS in the present work can be potentially used as a reflector for C and X bands.