Multifrontal method preconditioned GMRES-FFT algorithm for fast analysis of microstrip circuits

Purpose - Aims to apply the generalized minimal residual (GMRES) algorithm combined with the fast Fourier transform (FFT) technique to solve dense matrix equations from the mixed potential integral equation (MPIE) when the planar microstrip circuits are analyzed. Design/methodology/approach - To enhance the computational efficiency of the GMRES-FFT algorithm, the multifrontal method is first employed to precondition the matrix equations since their condition numbers can be improved. Findings - The numerical calculations show that the proposed preconditioned GMRES-FFT algorithm can converge nearly 30 times faster than the conventional one for the analysis of microstrip circuits. Some typical microstrip discontinuities are analyzed and the good results demonstrate the validity of the proposed algorithm. Originality/value - In the future, some more efficient preconditioning techniques will be found for the mixed potential integral equation (MPIE) when the planar microstrip circuits are analyzed.