Reconfigurable Metasurface with Varactor Diodes for Generation of Multi-mode OAM Vortex Beams

In this paper, we proposed a reconfigurable metasurface that can generate multi-mode OAM vortex beams with high purity in the X-band. The metasurface has two-dimensional reconfigurable properties and can realize arbitrary phase distributions. Then, by encoding the phase distribution of the meta-atoms, various OAM vortex beams including +1, +2, and +3 orders are generated, where the purity of all modes can be above 70%. As a validation, the metasurface composed of 30×30 meta-atoms is fabricated and measured. Both simulation and measurement results demonstrate the capability of the proposed metasurface to generate multi-mode OAM beams with high purity, indicating the application potentials of proposed meta-devices in future OAM communications.