A far-field approximation for the fast-multipole method applied to the combined field integral equation

A far-field approximation for the fast-multipole method is developed and applied to the combined field integral equation (CFIE), which is applicable for scattering from dielectric/magnetic material. In the examples presented, the performance of the method typically shows that both the matrix fill time and the storage are dramatically reduced to approximately 10% of that needed for the original CFIE.