Design of a wideband transmissive linear-to-circular polarization converter based on a metasurface

A wideband transmissive linear-to-circular polarization converter based on an anisotropic metasurface is proposed, which consists of three layers of conductive pattern layers separated by two dielectric layers, each conductive pattern layer consists of a square array of elliptical loop apertures. For the long axis of each loop aperture is tilted 45° from the vertical direction, and it is an orthogonal anisotropic structure with a pair of mutually perpendicular symmetric axes u and v along ± 45° directions with respect to y axis direction. Numerical simulation results show that the polarization converter can realize linear-to-circular polarization conversion at x and y polarized incidences in the frequency range from 10.73 to 16.13 GHz with a relative bandwidth of 40.2%. A detailed analysis for the polarization conversion was presented, and an effective formula was deduced, which can be used to calculate the cross- and co-polarization transmission coefficients at x and y polarized incidences according to the two transmission coefficients at u and v polarized incidences. Finally, one experiment was carried out, and a good agreement was observed between measured and simulated results.