A scheme of FDTD near-to far-zone transformation for scattering from an object over the curved earth is presented in this paper. With the equivalence principle
the eqUivalent electric and magnetic currents can be obtained from FDTD near fields output boundaries. The fields radiated by these currents in the presence of curved earth are then calculated using the reciprocity theorem and the known ground wave propagation formula of a vertical electric dipole (S. Rotheram
1992). Numerical results show excellent agreement between this scheme and analytical results. The feasibility of another approximate approach (Q. L. Li et al