The Galerkin's method solution of electromagnetic field integral equations for electromagnetic scattering problems of perfectly conducting object requires calculation of singular double surface integrals.The RWG(Rao-Wilton-Glisson) vector basis functions are usually applied as basis functions and testing functions.The singularity extraction technique and Duffy coordinate transformations have been traditionally used to treat these singular integrals.A more accurate and efficient method are presented.This new method removes the singularity in the integrand and allows the reduction in dimensionality of original 4-dimensional integrations by using combination of parametric coordinates

relative coordinates

domain decomposition and general Duffy coordinate transformations.The accuracy and good convergence properties of the new method are demonstrated by some numerical examples.