A Tri-Band, Highly Selective, Bandpass FSS Using Cascaded Multilayer Loop Arrays

A highly selective tri-band bandpass frequency-selective surface (FSS) is presented by cascading three layers of periodic arrays. The middle layer is composed of double square loops (DSLs) while the two exterior layers are composed of gridded-double square loops (G-DSLs) structure. The proposed FSS can provide multitransmission zeros which lead to a wide out-of-band rejection between each two adjacent passbands and sharp rejection behavior on both sides of each passband. Furthermore, the FSS exhibits stable response over a wide range of incident angles for both TE and TM polarizations. The design procedure, simulation, and experiment of the FSS are presented. The measured results are in good agreement with the simulations.