Abstract:Abstract: In this paper, a terahertz dual-beam leaky-wave antenna (LWA) based on a multi-mode spoof surface plasmon polariton (SSPP) waveguide is proposed. By dispersion engineering of the SSPP transmission line (SSPP TL), multiple modes are excited on the SSPP TL. A dual-beam LWA is constructed based on the radiation from the first space harmonics of the guided fundamental mode and the first higher-order mode. The simulation results show that the antenna radiates frequency-dependent dual beams in the 1.9-2.6 THz operating frequency band. The average gains for the two beams are 12.9 dBi and 8.2 dBi, respectively. The compact dual-beam LWA is promising in the application of wireless communication and radar systems.