Vortex beam generated by circular-polarized metasurface reflector antenna

Vortex beams with orbital angular momentum (OAM) can remarkably increase the channel capacity without signal process, thus attract more and more attention of researchers, and various novel methods of generating vortex beams blow out. In this work, a circular-polarized vortex beam reflector antenna was proposed via integrating vortex beam generated metasurface and beam focusing metasurface. The antenna consists of the metasurface reflector and a feed helical antenna. The phase distribution of the metasurface combines the OAM phase distribution and the beam focusing required phase distribution which is used to generate vortex beam from a point source. The measured results agree well with the simulated results, and both demonstrate that the reflector antenna can generate a vortex beam with OAM from 12 GHz to 18 GHz, and the realized gain is 22.4 dB at the center frequency 15 GHz. (paper)