Electric Field Radiated by a Dipole Antenna and Transmitted into a Two-Layered Lossy Half Space

摘要

The paper deals with the calculation of electric field radiated by a dipole antenna and transmitted into a lossy half space modelled as a two layered medium. The frequency domain formulation to determine the unknown current along the wire is based on Pocklington's integro-differential equation which is solved numerically by using the Galerkin Bubnov scheme of Indirect Boundary Element Method (GB-IBEM). The calculated current is then inserted into field formulas and the field transmitted into the ground is obtained. The presence of the three medium configuration, air-Iayer1-Iayer2, is taken into account by two approaches. The first approach, Fresnel transmission coefficient approximation, beside the electric properties of the media, accounts for the incidence angles at the interfaces air-layer1 and layer1-Iayer2. On the other hand, the Modified Image Theory (MIT) based approach assumes the normal incidence and simplifies the calculation which is particularly important for a direct time domain analysis. Computational examples present several scenarios for the different sublayer types. Comparison of the two approaches in frequency domain undertaken in this work serves as a benchmark for the future time domain modelling of multilayered subspaces which is more cumbersome and MIT based approach may seem as a plausible approach.