Generation and control of vortex waves using tunable metasurfaces

Abstract This paper proposes an actively tunable reflective metasurface containing solely addressable meta-atoms capable of continuous phase adjustment within the microwave frequency range. Each meta-atom’s response can be quickly and accurately adjusted by adjusting the external voltage applied to each meta-atom, thereby regulating the phase distribution of the unit structures on the metasurface. Successful generation with three modes of vortex beams. Additionally, focusing and non-diffracting vortex beams with limited beam radii are achieved by superposing the vortex phase profile with a focusing phase profile and a non-diffracting zeroth-order Bessel beam phase profile, respectively, by combining laboratory simulations and sample testing, demonstrating the metasurface's high-precision phase control capability in the reflective state. The presented scheme facilitates the development of metasurface devices with more functionalities. It exhibits significant potential for microwave fields, like intelligent wireless communication, antennas, and radars.