Multi-channel terahertz focused beam generator based on shared-aperture metasurface

Most of existing metasurfaces usually have limited channel behavior, which seriouslyhinders their development and application. In this paper, we propose a multi-channel terahertz focused beam generator based on shared-aperture metasurface, and the generator consists of a top square metal strip, a middle layer of silica and a metal bottom plate. By changing the position and size of the shared-aperture array, the designed metasurface can generate any number of multi-channel focusing beams at different predicted positions. In addition, the energy intensity of focusing beams can be controlled. The full-wave simulation results show that the metasurface achieves four-channel vortex focused beam generation with different topological charges, and five-, six-, eight-channel focused beam generation with different energy intensities at a frequency of 1 THz, which are in good agreement with the theoretically calculated predictions. This work can provide a new idea for designing the terahertz multichannel devices.