Multi-Orbital-Angular-Momentum-Mode Vortex Wave Multiplexing and Demultiplexing with Shared-Aperture Reflective Metasurfaces

As an alternative degree of freedom for wireless communications, orbital angular momentum (OAM) multiplexing and demultiplexing can be applied to achieve higher communication capacity. Metasurface has advanced ability to manipulate electromagnetic (EM) waves, and has gradually become an enabling EM technology for future wireless communications. It is meaningful and useful to combine the advantages of OAM and metasurfaces. Here we propose a multi-OAM-mode vortex wave multiplexing and demultiplexing scheme based on shared-aperture reflective metasurface. The specifically designed reflective metasurface can realize the corresponding OAM-mode modulations and demodulations of different incident carrier waves in the corresponding data channels. By modulating multiple data channels on multiple OAM modes, the multiplication of the communication capacity could be achieved. A prototype operating at microwave frequencies is designed, simulated, and fabricated for proof-of-concept illustration. To validate the OAM multiplexing and demultiplexing scheme, we conduct dual-channel OAM-mode transmission experiments, in which two shared-aperture reflective metasurfaces are adopted as the transmitter and receiver, respectively. This work paves the way for the metasurface-based OAM communication applications in future wireless communication technologies.