Application of the loose GMRES-FFT method to the integral equations for microwave circuits

In this paper, the microstrip circuit is analyzed in terms of the mixed potential integral equation (MPIE) by using of the rooftop-function expansion and the blaze-function testing technique, the integral equation is solved by the loose generalized minimal residual (LGMRES) method to accelerate iteration. Our numerical calculations show that the LGMRES can converge nearly 8 times faster than the conjugate gradient-fast Fourier transform (CG-FFT) method. A typical microstrip circuit is analyzed and the good results demonstrate the validity of the proposed algorithm.