Dual-band dual-circularly polarized and orbital angular momentum multiplexed reflectarray

In this letter, a dual-band dual-circularly polarized (CP) orbital angular momentum (OAM) multiplexed reflectarray (RA) is proposed, capable of generating vortex electromagnetic beams with distinct polarizations, mode numbers (l), and radiation directions across different bands. First, it presents an innovative approach to achieving dual-band dual-CP decoupling. Second, the proposed RA integrates multiple multiplexing techniques, including frequency, polarization and OAM. Specifically, a low-profile metasurface unit cell is designed, utilizing only a dielectric substrate and a metal patch, achieving a bandwidth ranging from 10.6 GHz to 18.1 GHz (52.2%). Furthermore, a RA constructed from these units fulfills the duplex communication requirements of Ku-band satellite systems. It generates a left-handed CP OAM beam with l=+1 in the downlink band (10.7-12.75 GHz), and a right-handed CP beam with l= -2 in the uplink band (12.75-18.1 GHz), with each beam exhibiting a distinct radiation direction.