Analysis and Design of Highly Selective Zero-Controlled Band-Pass Multilayer Frequency Selective Surface

Abstract

In this paper, the idea of cross-coupling is applied to realize zero-controllable high-selectivity band-pass frequency selective surface(FSS). The element consists of two resonant layers at the top and bottom and a coupling layer in the middle. Cross-coupling is introduced into the structure, which makes it have electric coupling, magnetic coupling and direct path. Two transmission zeros(TZs) are generated on both sides of the passband, thus realizing the filtering characteristics of fast roll-off. The mechanism of TZs generation is studied by using an equivalent circuit odd-even mode analytical method. Due to its centrosymmetric structure, the FSS has good angular stability and polarization stability. FSS samples with operating frequency at 19.25 GHz, low stop band at 18.2 GHz, and high stop band at 20.8 GHz were fabricated and tested experimentally. The FSS maintains stable performance at an incidence Angle of 75°. The measurement results are in good agreement with the full-wave and circuit simulation results, verifying the design of FSS.