Spoof Surface Plasmon Polariton Modes Propagating Along Periodically Corrugated Wires

In this paper, we analyze in detail the characteristics of surface electromagnetic modes that can propagate along a periodically corrugated, perfectly conducting wire. We show how these modes, termed spoof surface plasmon polaritons, resemble surface plasmon polaritons supported by metallic wires at optical frequencies. The important point is that the dispersion relation of spoof surface plasmon polaritons is mainly controlled by the geometry of the corrugation. This fact allows the tuning of the properties of these modes via changes in corrugation geometry. Important applications lie in high-confinement waveguiding at far-infrared and microwave frequencies, including the possibility of efficient propagation to the tip of tapered structures for focusing.