Spectral preconditioned CG-FFT method in electromagnetics analysis

Presents an efficient spectral preconditioned conjugate gradient fast Fourier (SPCG-FFT) method for EM analysis. This technique takes full advantage of the FFT by carrying out the CG operation, constructing the preconditioner and operating the preconditioning in the frequency domain. It also has the additional advantage that no additional memory and only O(NlogN) additional operations are needed for constructing and storing the preconditioner. At the same time it has superior convergence properties compared with the conventional CG-FFT method. Two numerical examples, a long wire antenna and a planar microstrip dipole array, are given to show the great potential of this technique in solving 1D and 2D large EM problems.