Mode-Reconfigurable OAM Reflectarray Based on Liquid Crystal Polymer

This paper presents a reconfigurable reflective metasurface based on liquid crystal (LC) materials to achieve multiple orbital angular momentum (OAM) mode-switching functionalities. The design features a resonant three-layer metal element operating at 0.12 THz as a Huygens’ metasurface. By introducing a cross structure with two concentric rings and a square ring at the edge of the unit, the phase response curve’s slope is reduced, thereby improving the robustness of the units. Leveraging the birefringence characteristic of liquid crystal material, we adjust the electric field intensity to control the units, achieving a phase variation range close to 270 degrees. Additionally, a bias circuit is integrated behind the interlayer metal through metal vias to enable pixelated array control. Theoretical calculations and full-wave simulations for three OAM modes are conducted, and the comparison of these results demonstrates that the proposed design can be effectively switched between OAM modes.