A comparative study of a class of FFT-based methods for the computation of electromagnetic scattering from 2 and 3D objects

A systematic comparison of three methods based on the different ways of generating variational basis functions in van den Berg´s algorithm is conducted. The MSIT is a matrix interpretation of the spectral iteration technique; the CGFFT (conjugate gradient fast Fourier transform) is obtained by an appropriate choice of basis function. A third choice, based on a generalized Neumann series (GNS) expansion of the inverse of the integral equation operator is proposed. Test cases in both 2 and 3D for a wide range of dielectric problems show that the GNS is more efficient that either the MSIT or the CGFFT irrespective of material composition, size or shape