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 pass-band 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 K alpha-band was fabricated and measured. Good agreement between the measurement and simulation results has been achieved.