Generation of orbital angular momentum and focused beams with tri-layer medium metamaterial

We propose a metal/dielectric tri-layer metamaterial for wavefront shaping. By arranging the element in an array with a constant phase gradient and irradiated it with a plane wave, focused and focused vortex beams can be obtained. The designed metamaterial features the excellent capability of focused/focused vortex beams generation within the operating frequency range of 30 GHz–34 GHz. The simulation results are consistent with the theoretical analyses.