Design and analysis of frequency-selective surfaces for ultrawideband applications

In this paper we investigate a multilayer frequency-selective surface (FSS) and its potential use in ultra wideband (UWB) antennas. A complete design and analysis of the FSS with an example UWB antenna is presented. The multilayer FSS provides an appropriate reflection phase to act as a reflector for the UWB antenna and is able to enhance its gain. A design guideline for the FSS is presented via a parametric study. Evaluation of the multilayer FSS with a UWB slot antenna shows a significant enhancement of gain across an ultra wideband (140%) impedance bandwidth. Its compact configuration provides flexibility for mounting the reflector close to the slot antenna geometry and makes it more suitable for various UWB devices. Simulations show a linear phase response across 4 to 12 GHz band which is sufficient for ultra wideband operation.