On the Use of Subwavelength Radial Grooves to Support Spoof Surface-Plasmon-Polariton Waves

This letter introduces radial grooves as a feasible geometry to support spoof surface-plasmon-polariton (SPP) waves propagating along a vacuum-metallic interface. Through the analytical derivation of a dispersion relation, validated also with full-wave simulations, the ability of radial grooves to operate in the fundamental mode at the microwave regime is demonstrated. Also, results demonstrate the utility of radial geometries to decrease the depth of the grooves, in comparison with the widely used rectangular grooves, thereby providing a superior methodology for generating spoof SPPs.