Controlling rejections of spoof surface plasmon polaritons using metamaterial particles.

Based on the dispersion relation, surface plasmon polaritons (SPPs) or spoof SPPs are always propagating surface waves when the operating frequency is below the asymptotic limit - the surface plasma frequency. Here we propose a method to control the rejections of spoof SPPs using metamaterial particles. By introducing electrically resonant metamaterials near an ultrathin corrugated metallic strip - the spoof SPP waveguide - to produce tight coupling and mismatch of surface impedance, we show that the SPP modes are rejected near the resonant frequencies within the propagating band. Through the modulation of scaling factor of metamaterial particles, we can manipulate the rejections of SPP modes from narrowband to broadband. Both simulation and experiment results verify the tunability of SPP rejections, which have important applications in filtering SPP waves in plasmonic circuits and systems.