Reflective Metasurface for Vortex Wave Generating and Divergence Reducing in X-Band

Abstract

In this paper, a novel and simple solution for generating vortex electromagnetic wave and reducing divergence simultaneously in a wideband is presented. Based on phase gradient metasurface, we design a metasurface that can convert an ordinary electromagnetic wave into a vortex one and focus the vortex wave in X-band. Double layer rectangular metal patch units of different sizes are arranged in a certain order to compose the metasurface. The phase introduced by the metasurface is superimposed by the vortex phase and focusing phase. Compared to a general vortex wave metasurface, the simulation results show that the divergence of the reflected vortex wave generated by our designed metasurface is dramatically reduced in the frequency range from 8 GHz to 12 GHz. It is indicated that the designed metasurface has a highly efficient focusing effect, and it is also in a good agreement with the theoretical analysis. The proposed reflective metasurface paves an effective way to reduce the divergence of vortex electromagnetic wave for OAM-based system in microwave and radio frequency.