Fast calculation of electromagnetic scattering from three-dimensional buried object

In this paper, the distance between source and field points is divided into ultra-near field region, near field region and far field region for fast and accurately calculating the spatial Green's function. The spatial Green's functions within the three regions are respectively calculated by the Langrage interpolation scheme, the DCIM with surface wave poles being extracted and the SDP with leaky wave poles being extracted. In this way, electromagnetic scattering from the electrically large buried object can be calculated fast and accurately. The numerical examples show that the presented method is accurate and efficient.