Electromagnetic scattering from smooth objects across layer interfaces

In this report the theory and a program for computing electromagnetic ELF scattering from a smooth perfectly conducting object positioned across layer interfaces in a stratified environment is presented. The program uses a boundary element method to compute the current density on the scatterer and the fields outside the scattering object. To be able to position the scatterer in multiple layers the mesh is refined so that no face in the mesh is positioned in more than one layer. To increase the speed of the program an approximation of the dyadic Green´s function within a face is presented which decreases computational time of the collocation integral with a factor of six. The results and convergence of the program are compared with a program based on a global Galerkin´s method for the case when the scatterer is positioned in one layer. Two numerical examples are presented in the end of the report.