Long range ground wave scattering of Low Frequency Antennas due to ground discontinuities

Ground wave radiation of Low Frequency Antennas is well known for the canonical case of a flat, azimuthally homogeneous, soil. In this paper, more complex kinds of environment like forests, hills, valleys, lakes... are considered with an original hybridization of a direct numerical integration of Sommerfeld's integrals with 3D FDTD. The results show that the effects of discontinuities are less important when they are located in the vicinity of the antenna and that major effects are close to the perturbed zone.