A dual layer wideband angular stable frequency selective surface for linear to circular and circular to linear polarization conversion for 5G applications

This work proposes novel transmission type frequency selective surface (FSS) for converting linear to circular (LP to CP) and circular to linear (CP to LP) polarizations. The structure has dual metallic layers sandwiching a dielectric substrate (Rogers RT5880). Both top and bottom metallic layers have the same unit cell structure. This transmission-type polarization converter has a maximum polarization conversion efficiency (PCR) of 99.98% with a bandwidth of 23.8% at 27.3 GHz. The structure is also angularly stable upto 60^o. Though the structure is designed for the 5G band, it is possible to tune this structure to the frequency of our interest. The novelty of the proposed design lies in a low structural complexity, tunable frequency range, and very high angular stability. This low-loss, wideband, and high angularly stable polarization converter FSS type is an advantageous alternative to conventional CP sources and can be used for communication purposes.