Surface waves

The paper is an attempt to present, in the simplest possible terms, a unified picture of the theory of various forms of surface wave and a clear physical interpretation of their behaviour. The Zenneck wave, the radial cylindrical surface wave and the Sommerfeld-Goubau or axial cylindrical surface wave are each discussed and shown to represent basically one and the same phenomenon. The link with the Brewster angle, for which a wave incident on a surface suffers no reflection, is clearly established. The transition from a TEM wave supported by a parallel-strip transmission line, with metal plates close together, to two Zenneck waves independently supported by the plates, when these are separated by a very large distance, is demonstrated. The effect of bends in the supporting surface is considered, and methods of reducing radiation are explained. Finally the principles governing the launching of surface waves are surveyed with particular reference to the Brewster-angle approach.