Reconfigurable band rejection frequency selective structures

Traditional frequency selective surfaces exhibit poor filtering responses due to their 2-D nature. To address this challenge, recent work has explored multilayer frequency selective structures (FSSs) to design practical rejection filters with sharp roll-offs. This is achieved by cascading several periodic surfaces into a single multilayer FSS that can be fine-tuned to achieve desired design parameters (B. Munk, Frequency Selective Surfaces: Theory and Design, 2000; B. Li and Z. Shen, IEEE Trans. Ant. Prop., 61, 3053-3059, 2013).