Electromagnetic field of arbitrarily oriented coil antennas in complicated underground environment

This paper presents a numerical algorithm based on the finite-difference method to simulate the electromagnetic fields generated by arbitrarily-oriented transmitter coils in a three-dimensional (3D) fully anisotropic medium. An edge-centered, staggered-grid finite-difference method is used to solve the vector equation for the scattered electric field. The resultant matrix equation is solved iteratively using a generalized minimal residual (GMRES) algorithm and an incomplete LU precondition technique is applied to improve the convergence behavior of the linear equation. A conductivity averaging technique and optimal grid refinement are also used in the approach to obtain further efficiency. Numerical examples will be presented to demonstrate the efficiency and capability of the present method.