Multiple-Polarization Multibeam Vortex Wave Generator With High-Gain and Low-Profile Characteristics

The generation and polarization multiplexing of vortex waves are of great significance to vortex wave communication systems and are worthy of further exploration and research. However, available multiple-polarization vortex beam generators suffer from a high profile. In this communication, we propose a new multiple-polarization vortex wave generator based on a folded transmitarray antenna (FTA) with high-gain and low-profile characteristics. The proposed vortex beam generator can generate a high-gain l = +1 and l = -1 dual-beam vortex wave operating at 19 GHz. Left-hand circular polarization (LHCP), right-hand circular polarization (RHCP), and linear polarization (LP) vortex waves can be generated by only changing the polarization of the LP feeding antenna. The fabricated vortex beam generator exhibits high gain (the maximum gains are 20.05, 20.03, and 20.63 dBi for RHCP, LHCP, and LP, respectively). The proposed vortex beam generator not only reduces the profile by 1/2 compared to the traditional reflection array and transmission array generators, but also has the advantages of high-gain, multiple vortex beams, and easy integration. Our work opens a door for the design of high-gain and low-profile multiple-polarization multibeam vortex wave generator.