Efficient method for the near-field scattering by buried dielectric and conducting objects

This paper presents an efficient method for the near-field electromagnetic scattering by three-dimensional buried dielectric and conducting objects, in which the interaction of source antennas, the ground, and scatterers is considered. With the excitation of a linear antenna, the electric field integral equations for the antenna and buried objects, and their radiation and scattered fields are formulated, which involve two different sets of Sommerfeld integrals. Because the evaluation of such Sommerfeld integrals needs tremendous CPU time, the integration along steepest-descent paths and leading-order approximations are introduced to accelerate the computation, in which the difference between the two sets of Sommerfeld integrals is addressed. As an example, the excitation of dipole and loop antenna is considered for the scattering by buried objects, which is important for the geophysical detection problem. Numerical results show that the efficient method can reduce tremendous CPU time compared with the numerical integration method.