High-Efficiency Conversion From Rectangular Waveguide Mode to Spoof SPP Using Metasurface

Abstract

In this letter, we propose a method to realize rectangular waveguide mode to spoof surface plasmon polaritons (SSPP) mode conversion using phase gradient metasurface (PGM). By applying a PGM with designed wavevector to the narrow wall of the rectangular waveguide, propagation mode and direction of the guided waves can be conversed and controlled due to wavevector matching. Such system can provide an excellent transition by matching the momentum of the rectangular waveguide mode and the SSPP mode. A smooth bridge between the rectangular waveguide system and the SSPP waveguiding system can be realized with potential advantages in conformal design, super-resolution imaging or signal manipulation. Simulated and experimental results, agreeing well with each other, validated the effectiveness of rectangular waveguide mode to SSPP mode conversion using PGM from 6.96-7.55 GHz. Furthermore, a dual channel rectangular waveguide to SSPP splitter is proposed and validated with applications for dual-channel power dividing and signal transmission, achieving an efficiency of 72.4%.