A Reflective Metasurface for Generating Orbital Angular Momentum Vortex Wave Across Wide Bandwidth

In this paper, a reflective metasurface is designed to generate orbital angular momentum (OAM)vortex wave across wide bandwidth at X band. The double square rings element which offers a slow slope of the reflected wave phase as approximately a linear function of the rings' length to achieve a wider operational bandwidth is utilized as reflective units to generate OAM vortex wave across a broad bandwidth of $9-12GHz$ . The prototype of this metasurface is simulated, manufactured and measured. The simulation and experimental results demonstrate the feasibility of this design methodology.