Scattering by a buried conducting object of general shape at low frequencies

A numerical method is described for determining the low frequency response of buried arbitrarily-shaped conducting objects due to a source located above the ground. The problem is formulated in terms of integral equations by replacing the object´s surface by the induced surface currents. The source frequency is assumed to be low enough so that a first order approximation can be used to simplify the formulation and reduce the computation time and memory. The simplified problem is then solved using the method of moments to reduce the integral equation into a matrix equation. The total scattered field is separated into two terms, one of which is the direct scattered field as if no buried inhomogeneity were present, the other is the anomalous field, which represents the presence of the inhomogeneity. The solutions are applied to the investigation of scattering by buried perfectly conducting spheroids. The numerical results show that the method can be useful in detecting buried objects.