A comparison of two FFT‐based methods for dielectric scattering problems

Abstract

The performance of two FFT‐based methods for solving dielectric scattering problems is investigated. The first method is associated with van den Berg's integrated‐squared‐error algorithm, where the variational basis function is based on a generalized Neumann series (GNS) expansion of the inverse of the defining integral operator. The second method is the biconjugate‐gradient FFT (Bi‐CGFFT) for symmetric indefinite systems. Both methods are applied to a variety of dielectric problems encompassing both homogeneous and inhomogeneous material compositions in twoand three‐dimensional spaces. Particular emphasis is placed on the identification of the class of problems that yield nonconvergence for the Bi‐CGFFT and the alleviation of this undesirable behavior.