Long-Range Three-Dimensional Ground Wave Propagation Modeling Over Flat, Irregular Terrain

Ground wave propagation of low-frequency (LF) electromagnetic waves is well known for the canonical case of a flat, azimuthally homogeneous, soil. Moreover, it is well investigated for realistic propagation problems, some of which include Earth's curvature, irregular and lossy terrain profiles, and mixed paths. In this paper, kinds of environment are considered in the far-field of the radiating antenna with an original methodology. It rests on the use of hybridization of finite-difference in time-domain (FDTD) with the direct numerical integration of Sommerfeld-type integrals which is also presented and validated. This hybridization uses domain decomposition and Huygens' surfaces in a stratified dielectric medium in three-dimensional (3-D) space. The approach is validated with respect to a reference solution both in the canonical flat ground case and in a hilly one.