A multilevel formulation of the method of moments [EM scattering]

The modeling of electromagnetic scattering and radiation problems using the method of moments (MoM) is limited to resonant frequencies because of the extensive computational requirements of solving large matrix equations. In this study, a multilevel formulation of MoM which allows substantial computational savings and, thus, extends the application of MoM to higher frequencies is presented. Using a hierarchy of discretization levels, the multilevel technique extracts different modal components of the solution by focusing on a specific portion of the spectrum of the solution at a given level. The fundamental features of this process for the MoM solution of the electric field integral equation (EFIE) are developed and implemented. This multilevel MoM allows the rapid evaluation of the current distributions on a variety of 2-D scatterers with thousands of unknowns in fewer than ten cycles and in fractions of the normal CPU times. The method is stable, fast, suitable for multiple excitations, and adaptable as a `solve´ module for almost any MoM code