Investigation of the projection iterative method in solving the MoM matrix equations in electromagnetic scattering

The projection iterative method (PIM) is convergence guaranteed when applied to solve the MoM equations with nonsingular matrices. Its decomposition procedure divides the matrix into some small subregions to avoid large matrix inversions. It is found that the convergence rate can be accelerated by introducing the relaxation factor to the PIM formulation. Three 3D examples are investigated to show the performance and validation of the PIM on electromagnetic scattering problems. A 2D infinite circular cylinder with TE field illumination is also studied to show the convergence of the method. The relationship of various PIM related parameters, such as the normalised residual norm, the number of iterations, the number of divided subregions, and the relaxation factor, is studied and presented, It is concluded that the operation count of the accelerated PIM is usually comparable to the direct method and the PIM can predict the RCS faster than the direct method with a reasonable accuracy