Modelling the effects of realistic environments in the nearfield and farfield of Low Frequency Antennas with 3D FDTD method

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 are considered in the surroundings of the antenna or in the far field. Both of them are treated by FDTD. Some realistic environments are studied in the near field zone including forest and slopes. An original methodology is proposed for the far field zone. It rests on the use of the direct numerical integration of Sommerfeld's integrals which is presented also.