Vortex Wave OAM Mode Conversion Device with Adjustable Amplitude and Phase Metasurface

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 important technology for future wireless communications. In this paper, we propose a transmission metasurface with adjustable amplitude and phase, which can control the OAM mode spectrum of vortex waves generated by vortex sources. A metasurface is applied as the vortex source, and another transmission metasurface is cascaded as a vortex wave OAM mode conversion device. By introducing weight coefficient of different OAM modes during the design process, the proposed vortex wave OAM mode conversion device can generate vortex waves with energy-distributed controllable OAM modes.