Broadband polarization rotator based on multi-order plasmon resonances and high impedance surfaces

We experimentally investigate the electromagnetic (EM) responses of a broadband reflective polarization rotator under normal incidence. It is found that the rotator can generate multi-order plasmon resonances at three neighboring frequencies. At each frequency, the rotator behaves as a high impedance surface along one axis while as a metallic reflective surface along the other axis. Thus, a 180 degrees phase difference is generated between the two orthogonal components of reflected waves. When the incident wave is polarized by 45 degrees with respect to the symmetry axis of the rotator, the polarization of reflected waves is rotated by 90 degrees. The designed rotator presents broadband properties. It can perform perfect 90 degrees polarization rotation at three frequencies and maintains a polarization conversion efficiency greater than 56% in 2.0-3.5 GHz. The rotator provides a route to broadband polarization rotation and has application values in polarization control. (C) 2013 AIP Publishing LLC.