Polarization-Insensitive Metasurface Lens for Efficient Generation of Convergent OAM Beams

A novel metasurface lens made of polarization-insensitive hexagonal units with honeycomb lattice is provided for generating orbital angular momentum beams. The unit is composed of multilayer capacitive hexagonal patches coupled through middle-layer inductive snowflake wire grids for a stable bandpass response. Due to the isotropy of the hexagonal unit and the honeycomb lattice of the cell arrangement, the proposed metasurfaces are polarization-insensitive, providing stable responses under different angles and polarizations of the incident electromagnetic wave.