Some Comments on the Time-Causal Characteristics of Leaky and Surface Waves.

摘要

The generation of surface waves on an infinite cylindrical antenna by a point source is examined, and the amplitude of the leaky-wave or the Goubau-wave, depending on the reactive surface loading, is determined. A Fourier-time analysis then gives the surface-wave transient, and in both cases it is found to take the form of a precursor outside the light cone. It is concluded that both these surface waves are non-causal in character, and that this property is likely to be a general one for isolated modes that individually do not satisfy the radiation condition. (Author)