Electromagnetic-wave propagation along a horizontal wire above ground

The electromagnetic-wave propagation along a horizontal wire in the presence of a lossy ground is analysed using a field approach. It is shown that, besides the proper solution, which has been considered by Kikuchi, the wave equation admits an improper solution, which is the relevant one for the Beverage antenna. The dispersion equations for these two modes are derived and solved by a numerical technique without making any assumptions about the order of magnitude of the transverse wavenumber. The validity of Kikuchi´s approximate method for evaluating the Fourier representation of the field (quasi-TEM approximation) is discussed. The results given by the theory for the propagation coefficients of the two modes are compared with those measured on a small-scale model.