High-efficiency spoof plasmon polariton coupler mediated by gradient metasurfaces

Abstract

Gradient metasurfaces (GMs) can provide pre-defined wave vectors that are along the surface of GMs. When the additional wave vector is greater than that of incident waves, the incident waves can be coupled efficiently as spoof plasmon polaritons (SPPs) even under normal incidence. In this Letter, the design of SPP couplers was proposed based on GMs. A high-efficiency SPP coupler was designed using split-ring resonators. Both the simulation and experiment show that the GM can achieve nearly perfect SPP-coupling under normal incidence at the designed frequency.