A Multitrace Surface Integral Equation Method for PEC/Dielectric Composite Objects

The multitrace domain decomposition surface integral equation (MT-DD-SIE) originally developed to analyze electromagnetic scattering from dielectric composite objects is extended to efficiently account for perfect electrically conducting (PEC) bodies. This is achieved by adopting Robin transmission conditions (RTCs) to PEC surfaces. These PEC-RTCs, which are the only governing equations for a PEC body, are used to “couple” it to the dielectric bodies. Upon discretization, PEC-RTCs produce a well-conditioned matrix block and, therefore, does not negatively affect the convergence of the iterative solution of the MT-DD-SIE matrix equation. The resulting method is significantly faster and has a smaller memory footprint than the traditional globally coupled contact-region-modeling method that uses the coupled electric field and Poggio–Miller–Chang–Harrington–Wu–Tsai SIEs in analyzing electromagnetic scattering from composite PEC/dielectric objects. This is demonstrated by numerical examples involving electrically large scatterers.