An accurate conjugate gradient fast Fourier transform method for electromagnetic scattering

An accurate conjugate gradient fast Fourier transform (CG-FFT) for solving electromagnetic scattering problems is developed by improving the accuracy of estimating the spectrum of the Green's function. Compared to the traditional CG-FFT algorithm, this new approach reduces the relative error by a factor of 5 to 20 for one-dimensional electromagnetic scattering models while maintaining the computational cost in terms of CPU time and memory requirement.