Cylindrical Waveguides for Microwave Spoof Surface Plasmon Polaritons

This work presents the theoretical and numerical design of a cylindrical waveguide that supports Spoof Surface Plasmon Polaritons (SSPP) at microwave frequencies. First, a theoretical model is proposed to assess the propagation of SSPPs in a cylindrical geometry and to estimate the surface impedance required to enable these wave modes. The reliability of the theoretical model is verified against numerical results. The proposed cylindrical waveguide embeds a cladding metasurface with a dielectric substrate covered by a lattice of square metallic patches. According to numerical estimations, the proposed design allows the propagation of SSPPs in the frequency range 2.2–5.7 GHz. Notably, the cut-off frequency is lowered by approximately 3.5 GHz with respect to conventional metallic solutions. The target application of the proposed waveguide is efficient plasma generation.