Design of a Bandwidth-Enhanced Polarization Rotating Frequency Selective Surface

An approach for the bandwidth enhancement of a polarization rotating frequency selective surface (FSS) based on the substrate integrated waveguide (SIW) technology is proposed in this communication. Compared with the previously reported polarization rotating FSS, the passband bandwidth of the proposed FSS is enhanced from 4.6% to 7.2% by introducing a triple-mode SIW cavity resonator as the periodic element. Meanwhile, better frequency response selectivity of filtering performance is achieved. The proposed FSS is made up of a periodic array of the novel triple-mode SIW cavity resonators with two orthogonal slots on the front and back surfaces for polarization rotation. The triple-mode SIW cavity resonator is achieved by placing a metallic via at the center of a dual-mode SIW cavity resonator. Bandwidth enhancement of the FSS is achieved by simultaneously exciting and properly merging together these three modes in the SIW cavity resonator. A prototype designed at Ka-band was fabricated and measured. Good agreement between the measurement and simulation results has been achieved.