Dual rhombic loop-based frequency selective surfaces for X-band applications

Abstract

Dual rhombic loop (DRL) based low-cost X-band frequency selective surfaces (FSSs) with stopband characteristics are presented in this study. Orthogonally oriented arrays of rhombic loop pairs are printed back-to-back (BTB) on both sides of dielectric substrate to achieve wide stopband characteristics with stable response under oblique incidences. The nonlinearities in the reflection phase of BTB DRL printed FSSs are compensated by printing orthogonally oriented rhombic loop pairs on the same side of the substrate. Merging orthogonally oriented rhombic loop pairs results in a single-layer wide stopband FSS with linear reflection phase under normal incidence. Both polarization dependent merged DRL (MDRL) and independent BTB DRL FSSs are developed and experimentally validated. As per measurements, the BTB printed FSS array exhibits 4.3 GHz wide stopband with transmission nulls at 7.9 and 10 GHz while the single side printed FSS exhibits 3.7 GHz wide stopband with transmission null at 8.3 GHz