An efficient chiral polarization rotator with asymmetric transmission for large incidence angles

A linear polarization converting chiral metasurface with asymmetric transmission is designed, analyzed, and characterized experimentally for operation in the Ku band of the microwave frequency regime. The proposed structure consists of two metasurface layers of asymmetric square-shaped unit cells with quarter moon polygon split-ring resonators. By breaking certain symmetries of the chiral structure, the proposed structure achieves efficient asymmetric transmission with the asymmetric transmission parameter of more than 80% and a polarization conversion ratio of more than 90% for 13.87-16.04 GHz. Moreover, the proposed structure gives a stable response to the variations in the incidence angle up to 45° both for transverse-electric and transverse-magnetic polarizations. The high efficiency for both asymmetric transmission and polarization conversion, wide bandwidth, and angular stability qualify the proposed design for numerous microwave applications.