A robust surface integral equation formulation for conductive media

Conductive materials are widely encountered in solving real-world problems. The conductivities of different materials from good isolators to good conductors vary over an extremely large range. No existing methods can accurately solve problems over a broad range of conductivities. A new surface integral equation (SIE) formulation is proposed by tuning the coefficients for the external and internal equations. The presented formulation provides satisfactory performance over a significantly larger range of skin depths than existing SIE formulations. It is also confirmed that the mesh density does not necessarily follow the increasing wavenumber for the conductive region as long as the mesh is fine enough to approximate the solution. It can work in tandem with techniques that improve the integration accuracy to enlarge further the solvable range of conductivities.