A method to analyze scattering from general periodic screens using fast fourier transform and conjugate gradient method

A technique to analyze general periodic screens is presented. This technique uses the Conjugate Gradient (CG) method and the aliasing effects that appear when discretizing the Green´s function in the spectral domain. The technique is computationally efficient because it does not require any summation of Floquet´s harmonics in the real domain and because using the FFT to evaluate the convolutions that appear in the CG method reduces the computing time and avoids the manipulations of large matrices. Some results of current distributions are presented.