A far-field approximation for the fast-multipole method applied to dielectric scatterers in the resonance region

A full wave 3D moment-method (MoM) analysis is discussed which has had a far-field approximation introduced to simplify the application of the fast-multipole method (FMM). The embedded FMM is applied to the combined field integral equation, which is applicable for scattering from dielectric/magnetic material. Far-field scattering and surface currents computed by the FMM and the original MoM are shown to be in good agreement.