Dual-Polarized 1-Bit Reconfigurable Reflectarray for Generating Digital Vortex Beam

A design for a dual-polarized 1-bit reconfigurable reflectarray antenna (RRA) based on PIN diodes has been proposed. The PIN diodes are integrated onto each reflectarray element and their operating states are changed by applying an external DC bias voltage, enabling independent control of the electrical parameters of each element in two orthogonal directions. By arranging the operating states of the reflectarray elements according to the expected OAM mode, independent generation of X-polarized and Y-polarized OAM beams can be achieved. As a validation, a prototype of the RRA with a 16×16 elements was simulated at 12.5 GHz in the Ku band. The simulation results showed that the RRA could generate OAM beams with mode l = + and l = +2 in the X and Y polarizations, respectively, with corresponding mode purities of 85% and 81%. The RRA also achieved polarization multiplexing based on the OAM beam mode multiplexing, providing new degrees of freedom to address the scarce spectrum resources in the wireless communication and radar detection.