Transparent metasurface for generating microwave vortex beams with cross-polarization conversion

In this paper, metasurfaces with both cross-polarization conversion and vortex beam-generating are proposed. The proposed finite metasurface designs are able to change the polarization of incident electromagnetic (EM) waves to its cross-polarization. In addition, they also can modulate the incidences into beams carrying orbital angular momentum (OAM) with different orders (l = +1, l = +2, l = -1 and l = -2) by applying corresponding transmission phase distribution schemes on the metasurface aperture. The generated vortex beams are at 5.14 GHz. The transmission loss is lower than 0.5 dB while the co-polarization level is -10 dB compared to the cross-polarization level. The measurement results confirmed the simulation results and verified the properties of the proposed designs.