Design of an aperture coupled frequency selective surface

Two methods has been proposed to improve frequency selective surfaces´ cut-off of sidebands, that´s, three-order characteristics and transmission zero characteristics. The three-order characteristics is achieved with the design of one-order resonant coupling aperture and the transmission zero characteristics with the design of two coupling channels between patch unit and intermediate aperture. Also, the frequency selective surface has been miniaturized to improve its angle stability, which is achieved by unit interdigitated methods. The above methods are all simulated and optimized with numerical simulation (finite-element method) and the final design characteristics are validated with experimental results.