Design of Multi-layer Ultra-thin Frequency Selective Surface with Dual Bandpass Response

A multilayered dual-band frequency selective surface (FSS) with high selectivity is proposed in this paper. The unit cell of the presented FSS is a five-layered structure surrounded by a thin metal waveguide and has a very small thickness. The electromagnetic coupling is improved by the multilayer structure and the waveguide structure, which improves the selectivity of the FSS. Simulation results show that the proposed dual-bandpass FSS exhibits sharp roll-off characteristics and high out-of-band suppression, which are due to the introduction of three transmission zeros. The designed FSS can achieve the stable frequency response to the variations of the incident angle from 0° to 60°.