A general treatment for the electromagnetic modeling of composite structures with the method of moments

For more than twenty years, especially since the advent of the well known and extensively used Rao-Wilton-Glisson (RWG) subdomain functions, a lot of accurate electromagnetic modelling with the Method of Moments (MoM) has been accomplished, firstly and mainly for Perfect Electric Conductors (PEC), later also for dielectric bodies. Composite structures made of adjacent homogeneous PEC and dielectric bodies has received much fewer attention so far [2]. To date, though quite general approaches have been presented [3], no full treatment of this problem has been given yet. The purpose of this paper to make new steps towards such a full treatment. First of all, the PEC bodies are presented along with their dual counterpart, the PMC bodies. Next, both volumic bodies and plates are combined in every possible ways. The concepts of singular edges and branched bodies are introduced, and the importance of electrical continuity is emphasized. The essential notion of RWG sectors is identified, for which two important properties are demonstrated. The treatment of composite structures is made very general to allow the use the any testing scheme, coupled to any redundancy reduction scheme. Finally, a new general approach based on the sector property table is proposed where perfect conductors appear as a special case of dielectrics.