A Quad-Band Frequency Selective Surface With Highly Selective Characteristics

In this letter, a new quad-band frequency selective surface (FSS) is designed by cascading three metallic layers separated from one another by two thin dielectric substrates. Each exterior layer is a periodic array of gridded-triple square loops (G-TSLs) while the middle layer is an array of double square loops (DSLs). Two adjacent pass-bands are separated by two transmission zeros, which leads to a sharp rejection response on both sides of each band. Both the simulated and measured results validate the performance of the proposed FSS.