Electric field radiated by a dipole antenna above a lossy half space: Comparison of plane wave approximation with the modified image theory approach

The paper deals with the comparison between the two approaches to account for the presence of a two media configuration when calculating the electric field radiated by the dipole antenna. The first approach features the well-known Fresnel reflection/transmission coefficient approximation which, beside the electric properties of two media, considers also the incidence angle at the interface. On the other hand, the Modified Image Theory (MIT) approach uses the approximation of a normal incidence, thus neglecting the refraction of the wave in the lower medium. The MIT approach thus simplifies the formulation thus providing the analytical solution and the derivation of the time domain computation. In this paper the frequency domain formulation is used. It is based on the Pocklington's integro-differential equation which is solved numerically using the Galerkin Bubnov scheme of Boundary Element Method. The results obtained by both approaches are compared and conclusions are given regarding the limitations and strengths of the MIT approach with respect to the Fresnel coefficients approximation. The comparison undertaken in this work can serve as a benchmark for the analytical solution modeling and time domain modeling.