Multi-layer frequency selective surfaces with wideband response and their modelling

In this paper, novel frequency selective surfaces (FSS) with ultra-wideband (UWB) absorption are proposed, as well as a simple circuit model which can be used for their design. Multi-layered unit cell is realized using square ring resonators and various parameters and their effect on the FSS transmission performances have been analysed. In order to demonstrate the applicability of the proposed unit cell in the design of UWB FSS, two examples are proposed, one FSS that operates at 13.9 GHz and consists of 3 layers, and another one: a 4-layered FSS that operates at 13.3 GHz. Simulation results show that the proposed surfaces exhibit highly selective stop bands with fractional bandwidths of more than 52%, in the case of normal incidence.