Calderon Preconditioned Surface Integral Equations for Composite Objects With Junctions

A Calderon preconditioned (CP) surface integral equation method is developed for the analysis of scattering by piecewise homogeneous dielectric and composite metallic and dielectric objects. The method is based on the electric current formulation (ECF), which only uses the electric surface currents as unknowns. In the ECF the ill-conditioned electric field integral operator and the well-conditioned magnetic field integral operator appear on separate equations, making the application of the CP much easier than e.g., in the PMCHWT formulation where these operators are mixed. In particular, using ECF, Calderon multiplicative preconditioner (CMP) can be straightforwardly extended for composite objects with junctions. Numerical examples demonstrate that the developed formulation, CMP-ECF, is well-conditioned on a very broad frequency range.