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

This letter introduces radial grooves as a feasi- ble 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 SPPsThis work was supported in part by the Spanish and Andalusian research programs TEC2013-48414-C3-01 and P12- TIC-1442. The authors would like to thank the Spanish Ministry of Education-Commission Fulbright Program “Salvador de Madariaga” (PRX14/00320) for sponsoring the joint research between author