High performance reflective microwave split-square-ring metasurface vortex beam generator

Abstract

The creation of vortex beams becomes increasingly important in microwave region for their potential applications in high-capacity multiplexed wireless communication systems. In this paper, we propose a kind of split-square-ring metasurface for generating microwave vortex beams at 16 GHz. We first analyze the S-parameter of the meta-atoms and then optimize and pick up 8 units which can cover 2π phase shift for the whole array design. Four metasurfaces carrying topological charges from 1 to 4 are, respectively, designed, and full-wave simulation is utilized for evaluating the near-field performance. The orbital angular momentum purity for each topological charge is calculated. Meanwhile, the far-field property has also been simulated and measured, and the simulation results agree well with those in experiments. Our metasurface device provides a flexible way for generating high-quality vortex beams in the microwave region.