Improved Surface Integral Equation-Based Formulation for Characteristic Modes of Composite Metallic-Dielectric Objects

We propose an improved surface integral equation-based formulation for the characteristic modes of composite metallic-dielectric objects. The equivalent electric or magnetic current on the surface of dielectric body is alternatively involved to suppress spurious modes. Compared to the existing formulations, the proposed approach provides a natural and straightforward way to handle multi-layered structures. Numerical results validate the accuracy of the proposed formulation.