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

• Published in: Micromachines (Basel) Vol. 13; no. 7; p. 1117
• Main Authors: Yu, Jiayu, Zheng, Qiurong, Tang, Xueqin, He, Jie, Liu, Jie, Zhang, Bin, Zou, Kun
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 15.07.2022; MDPI
• Subjects: Angular momentum; Broadband; Circular polarization; Communications systems; Efficiency; Electron beams; Far fields; Frequency scanning; Metasurfaces; Methods; microwave passive metasurface; Multiplexing; orbital angular momentum; Pancharatnam–Berry phase; Phase distribution; Signal processing; vortex beam; Vortices; Wave generation; Wireless communication systems; Wireless communications; China
• ISSN: 2072-666X; 2072-666X
• DOI: 10.3390/mi13071117

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 2π 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°–24.9° and 17.9°–39.1° at φ = 315° and 135° 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.