Demonstration of terahertz spoof surface plasmon polariton waveguides using coplanar striplines with internal corrugations

This paper presents the design and experimental verification of a terahertz (THz) spoof surface plasmon polariton (SSPP) waveguide using a coplanar stripline (CPS) with internal corrugations and is compared against an external corrugation configuration. Internal corrugations are selected to reduce the insertion loss by improving the mode conversion efficiency of the transition circuit. We examine this effect using simulation and then experimentally confirm that the SSPP mode was excited for two different corrugation depths, 55 µm, and 65 µm. We found that the associated SSPP band-edge frequency changed from 0.89 THz to 0.72 THz which is consistent with the simulations.