Bi-Isotropic Huygens' Metasurface for Polarization-Insensitive Cross-Polarization Conversion and Wavefront Manipulation

A bi-isotropic Huygens' metasurface (BIHMS) is proposed for polarization-insensitive cross-polarization conversion and wavefront manipulation, which can transmit and twist a linearly polarized (LP) incident wave with arbitrary azimuth to its cross-polarized component, meanwhile, the phase shift of the transmitted wave can be manipulated within 0π -2π . The BIHMS unit cell contains four patch-via-patch (PVP) structures that form a fourfold rotational symmetry; each PVP structure consists of two orthogonally placed patches connected by a via, only with two layers of metal. As a proof of concept, a polarization-insensitive cross-polarization converter (PICPC) and a polarization-insensitive phase gradient metasurface (PIPGM) are proposed based on the unit cell. The simulated and measured results show that the PICPC exhibits a -1 dB cross-polarization transmission bandwidth within 8.4-11.2 GHz (27.7%) and the corresponding polarization conversion ratio (PCR) is over 92% under transverse electric, 45° LP and transverse magnetic incident waves, and the PIPGM deflects the different LP incident waves to the same direction within 8.6-10.8 GHz (22.7%) with efficiency over 60%. The proposed broadband BIHMS exploits a new option for polarization-insensitive electromagnetic (EM) manipulation and can find application in various wireless systems.