A volume adaptive integral method (VAIM) for 3-D inhomogeneous objects

This article describes a volume adaptive integral method (VAIM) for electromagnetic scattering from three-dimensional (3-D) inhomogeneous objects. By projecting the unknown current density within an arbitrary element in the inhomogeneous object onto a fictitious uniform grid, this method calculates the far-zone interactions of basis and testing functions through the fast Fourier transform, thus greatly reducing the memory requirement to O(N) and CPU requirement to O(NlogN), where N is the number of unknowns. The numerical results have been validated by the method of moment.