Surface waves supported by cylindrical surfaces

In approaching a discussion of this matter, it is most important to ensure general agreement about the particular features that characterize the so-called surface wave. An attempt has been made to formulate in simple and unambiguous terms a definition of this form of wave, distinguishing it from the various other waves known to be associated with an interface between two different media. It is maintained that there are really two closely allied aspects of the problem of surface wave propagation, one of which is more particularly concerned with launching the wave from a given aerial over the surface and the other with the capabilities of that surface in supporting such a wave. The present paper deals with the latter consideration in relation to surfaces slightly curved in the direction of the propagation of the wave. Recognizing the evanescent character of the surface wave field distribution over the equiphase surfaces and the important part played by the inclination of these surfaces with the normal to the interface when power is transferred across it, a method is discussed of calculating the radiation which arises when a wave of this kind circulates around a highly reactive supporting surface of cylindrical form. It is concluded that when the surface has a finite loss there will be a particular radius of curvature for which no power is transferred across the interface.