Continuous and discrete formulations for modeling electromagnetic wave propagation over an impedance ground in low troposphere in 3D

A 3D discrete mixed Fourier transform method is proposed for modeling the wave propagation over an impedance ground in 3D. The continuous and discrete formulations of the propagators are presented. The discrete formulation achieves self-consistency with respect to the discrete electromagnetic theory. Numerical tests are performed to compare the two propagators. Both are shown to be accurate. Therefore, the self-consistent propagator should be preferred.