Dual-Band Frequency Beam-Scanning Antenna Based on Quasi-One-Dimensional Spoof Surface Plasmon Polaritons

This paper proposes a dual-band frequency beam scanning antenna based on a quasi-one-dimensional (QOD) spoof surface plasmon polaritons (SSPP) structure realized by ringshaped patches. The proposed antenna achieves independent and adjustable wide-angle beam steering across dual frequency bands through the simultaneous control of electromagnetic wave radiation in the fast-wave and slow-wave regions. The QOD SSPP transmission line operates in the fast-wave region at higher-order modes, allowing electromagnetic wave radiation to be achieved in the high-frequency band without additional structures. Meanwhile, the SSPP line supports slow-wave transmission, and the ring-shaped patch array also enables a second operating frequency band in the low-frequency range. An antenna prototype was fabricated, demonstrating large-angle beam scanning of 85° and 52° in dual bands (5-8 GHz and 11.5- 15.5 GHz, respectively). Additionally, the design of the ringshaped patches achieves high RF transmittance, with a measured peak of 90% across the antenna's operational frequency bands.