Dual-band frequency selective structure with large frequency band ratio

A dual-band bandpass frequency selective structure (FSS) with large frequency band ratio is presented in this paper. The proposed FSS consists of an array of three-layer printed circuit boards and a number of inserted metallic rods and plates. Under a linearly polarized incident wave with its electric field perpendicular to the printed circuit boards, two propagation paths with four resonators are constructed, providing dual-band performance. Furthermore, the two operating passbands are determined by resonators in the two propagation paths, respectively, which can be designed independently. In order to verify our concept, a design example is given and its simulated results show that the proposed FSS exhibits stable dual-band performance with large band spacing under a large variation of incident angle.