Investigation of mechanism: spoof surface plasmon polaritons on composite periodic metal metasurface with multi-grooves.

A periodically corrugated metal metasurface can support spoof surface plasmon polaritons (SSPPs) at lower frequencies (e.g., terahertz (THz) and microwave ranges). In this paper, we explore a multi-bands SSPPs waveguide composed of a composite periodic metal groove (CPMG) and derive the theoretical dispersion formulas by the modal expansion method (MEM) under the deep subwavelength condition. The numerical experiments and analytical calculations are used to give a general analysis about the properties of the SSPPs on the composite periodic waveguides. It is demonstrated that the SSPPs waveguides of CPMG with multi-grooves in one period give better near-field confinement benefiting from the more electromagnetic (EM) hotspots at the surface of their periodic structure. Numerical simulations are employed to verify the theoretical analysis and demonstrate good agreement with the analytical results. The calculation methodology presented in this paper can be applied to address the miniaturization, compact design aspects of THz devices and highly sensitive trace sensing fields. [ABSTRACT FROM AUTHOR]