Ultrathin dual-mode orbital angular momentum generated based on dual-polarization coding metasurface

Abstract

In this paper, an dual-polarization 4-bit coding metasurface is proposed to achieve the flexible manipulation of different polarization electromagnetic wave reflection angles and the generation of dual-mode vortex beams by independent manipulation of orthogonal linearly polarized waves. The proposed metasurface is composed of H-type metal patch, dielectric substrate, and metal grounding layer from top to bottom. To prove the proposed concept, we design and fabricate four coding metasurfaces based on superposition theorem and holographic theory. One of the coding metasurfaces is designed to verify the ability to manipulate the beam angle, and each of the other three coding metasurfaces is designed to carry a vortex beam with different topological charges under orthogonal linearly polarized waves with a central frequency of 24 GHz. The experimental results show that the theoretical design is highly consistent with the simulation results. Therefore, it is verified that our proposed 4-bit dual-polarization coding metasurface has strong and flexible ability to manipulate the beam reflection angle and generate high performance dual-mode vortex beam antenna. Because of the wide application prospect of vortex beam in communication field, we have reason to believe that the proposed ultra-thin dual-mode vortex generator will have potential applications in wireless communication system in the fields of image and microwaves.