Analytical Forward Modeling of Scattered Electromagnetic Field by a Buried Cylinder under the Ground

This paper presents an analytical method for solving the electromagnetic (EM) field scattered by a cylinder buried in a multilayered medium, excited by a triaxial magnetic dipole located above the ground. The cylinder can be a perfect electrical conductor (PEC) or a dielectric characterized by conductivity, permeability, and permittivity. In the derivation, a set of reflection/transmission coefficients is introduced to describe propagation within the plane-stratified medium. Mutual transformation equations between plane waves and cylindrical waves are then employed to seamlessly integrate the wave propagation descriptions for the stratified medium and the cylindrical object. Consequently, the analytical solution for the scattered EM field is derived in the spectral domain. This solution incorporates an iterative equation representing the multiple interactions between the cylinder and the planar interfaces. Numerical results validate the proposed formulation and investigate the characteristics of the scattered fields. These formulations are suitable for forward modeling in EM geophysical prospecting applications.