Analysis of a joined split-ring FSS structure characterized by three resonant frequencies and a tuned enhanced band using the WCIP method

This work presents the analysis of a joined split-ring frequency selective surface (FSS) for X-band applications using the wave concept iterative procedure (WCIP). When the incident normal plane wave is polarized in the $x$ direction, the joined split-ring FSS shows three rejecting bands at 9 GHz, 10.5 GHz, and 11.5 GHz simultaneously with bandwidths of 3.11 GHz, 0.6 GHz, and 1.13 GHz, respectively. Moreover, one rejecting band at 6.5 GHz is present when the FSS is fed with a normal plane excited in the $y$ direction. In addition, the different resonant frequencies can be tuned independently to give rise to a tuned enhanced band. An FSS with four rejecting bands is obtained when the metallic notch is placed on the lower coupling metallic strip. The joined split-ring FSS is manufactured and measured. The simulated results obtained using the WCIP are compared to the measured results and COMSOL Multiphysics results and good agreement is obtained.