A Flexible Ultra-Thin Transmission Line Based on Spoof Surface Plasmon Polaritons

This paper presents a flexible ultra-thin spoof surface plasmon polariton transmission line structure. A two-conductor, four-stage transition structure is designed to achieve effective impedance and momentum matching between SSPP waves and transverse electromagnetic waves by varying groove depth. Simulation results indicate that the proposed transmission line exhibits high efficiency, with S11 < -10 dB from 1.8 GHz to 8.9 GHz and S21 > -3 dB from 0 GHz to 8.9 GHz. The results validate efficient excitation and excellent transmission performance. This work underscores the strong field confinement of the SSPP transmission line and highlights the potential of SSPP transmission lines for miniaturization, flexibility, and integration in high-frequency communication systems.