Bridging the Gap Between Plasmonics and Zenneck Waves

Due to the broad spectrum and versatility of electromagnetics, progress and new discoveries in this field have not made a uniform history. The same and similar phenomena are reinvented by researchers whose interests center on different frequency ranges. Surface waves make an illustrating example. Starting from the works of Sommerfeld and Zenneck, the theory of radio waves over ground was developed during the early and mid-20th century. In the latter part of the century, surface waves were independently studied from the point of view of localization of radiation, in connection with the optical properties of metals. The most-recent development of the present century is that plasmonics and terahertz applications meet microwave studies in the framework of the new discipline of metamaterials. The present article tries to bridge the gaps of surface waves over the various spectral ranges. The paper discusses the properties of the generalized Zenneck wave, including phase and attenuation characteristics of structures with different materials (dielectric, epsilon-near-zero, negative-permittivity plasmonic), backward-wave regimes, polarization properties, and singularities that take place when the ratio of the permittivities of the two media is -1.