Efficient solution of 3-D vector electromagnetic scattering by FMM with partly approximate iteration

The fast multipole method (FMM) with partly approximate iteration is developed for efficient solution of EM scattering from a conducting object with large electrical size. An appropriate critical iterative error (CIE) is used to switch the FMM into approximate calculations, in which only the contributions from nearby groups are considered. The present method can solve efficiently not only the bistatic RCS of an object but also the monostatic RCS of an object It can also be combined with other efficient techniques to achieve a faster algorithm.