Enhancing Wireless Communications via Orbital Angular Momentum Schemes enabled by Reconfigurable Holographic Metasurfaces

This paper studies finite-aperture holographic metasurfaces and provides a methodology to accurately evaluate and shape their electromagnetic response in terms of the scattered wavefront. Special focus is given to the use of vortex beams, carrying orbital angular momentum (OAM), with detailed analysis on transformation between plane-wave beams and vortex beams for non-trivial cases of oblique incidence in combination with wavefront shaping, i.e., steering and focusing. The results demonstrate that properly tuned reconfigurable holographic metasurfaces can effectively support multiple variable-order OAM beams, wavefront shaping and de/multiplexing, establishing their potential for future wireless communication systems and offering a promising pathway toward high-efficiency, secure, and high-capacity communications.