Frequency Scanning Dual-Mode Asymmetric Dual-OAM-Wave Generation Base on Broadband PB Metasurface

Increasing information capacity is significant for high-speed communication systems in a congested radio frequency sequence. Vortex waves carrying mode orthogonal orbital angular momentum (OAM) have gained considerable attention in recent years, owing to their multiplexing quality. In this study, a broadband Pancharatnam-Berry (PB) metasurface element with a simple structure is proposed, which exhibits an efficient reflection of the co-polarized component and a full 2 pi phase variation in 10.5-21.5 GHz under circularly polarized wave incidence. By convolution and addition operations, the elaborate phase distribution is arranged and the corresponding metasurface-reflecting dual-mode asymmetric dual-OAM waves is constructed. Under continuous control of the working frequency, the OAM vortex beams with the topological charges 1 and -1 are steered to scan within the angle range of 11.9 degrees-24.9 degrees and 17.9 degrees-39.1 degrees at phi = 315 degrees and 135 degrees planes, respectively. The simulation and measurement results verified the feasibility of generating frequency-controlled asymmetric dual beams and the validity of dual-mode OAM characteristics, both in the near and far fields. This design approach has considerable potential in OAM wave multiplexing and wireless communication system transmission.

Automated summary

This study proposes a broadband Pancharatnam-Berry (PB) metasurface element with efficient reflection and phase variation, and successfully constructs dual-mode OAM waves. By frequency control, OAM vortex beams can be scanned in different planes. Simulation and measurement results verify the feasibility and effectiveness of this design, demonstrating its great potential in OAM wave multiplexing and wireless communication system transmission.