Iterative near-zone preconditioning of iterative method of moments electric field integral equation solutions

A preconditioning operator for iterative solution of the electric field integral equation as applied to metallic scattering objects is iteratively computed employing the generalized minimal residual algorithm (GMRES). Using the strongest method of moments matrix elements only (typically in the near zone), iteration of the sparse preconditioner converges very quickly. In contrast to direct factorization of the near-zone matrix, no matrix fill-ins must be handled. Excellent convergence of the preconditioned system using GMRES again is demonstrated by scattering computations for a rectangular metallic plate and a metallic cube.