Improving the convergence of the iterative solution of matrix equations in the method of moments formulation using extrapolation techniques

A strategy is presented for improving the convergence of iterative solvers when used for solving the matrix equations of the method of moments (MOM) formulation of EM scattering problems in a frequency sweep. Based on the use of an initial guess, which is derived via an extrapolation procedure involving the solution obtained at previous frequency steps, this procedure improves the convergence behaviour over the use of either a zero initial guess or the employment of the solution at the last frequency as the initial value for conjugate gradient (CG) iteration.