Accurate FMM-CG-FFT algorithm for efficient analysis of large-scale periodic structures with finite sizes

In this paper, a new fast and accurate algorithm is specially designed to solve the scattering and radiation problem of large-scale periodic structures with finite sizes, in which the unit cell has an arbitrary shape. The new method which is referred as FMM-CG-FFT employs the priority of both the fast multiple method (FMM) and the conjugate-gradient fast Fourier transform (CG-FFT). Numerical results prove the efficiency and accuracy of the new algorithm.