End-fire antenna based on the higher-order mode of quasi-one-dimensional spoof surface plasmon polaritons

This paper proposes an end-fire antenna based on the higher-order mode of quasi-one-dimensional spoof surface plasmon polaritons (QOD-SSPPs), which exhibits high RF transmittance characteristics. A transmission line composed of two asymmetric quasi-one-dimensional SSPP units is employed to design the end-fire antenna. The dispersion characteristics of both the fundamental modes and higher-order modes of the QOD-SSPP unit are studied. The odd mode of the higher-order mode is used to achieve maximum gain in the end-fire direction for the first time. The antenna obtains a maximum gain of 10 dBi in the end-fire direction within the frequency band of 13.7–14.7 GHz. In the frequency band of 11.5–17.5 GHz, the antenna’s RF transmittance reaches a maximum of 90%. The measured results closely match the simulation results. Compared to traditional two-dimensional SSPPs, quasi-one-dimensional SSPPs exhibit better RF transmittance and field confinement, making them more suitable for stealth device design.