Combined Field Integral Equation Using Multibranch RWG Functions for Electromagnetic Scattering From Piecewise Homogeneous Dielectric Objects With Junctions

A new method that utilizes multibranch Rao–Wilton–Glisson (MB-RWG) functions and the electric and magnetic current combined field integral equations is proposed for analyzing piecewise homogeneous dielectric targets of arbitrary shapes with junctions. The proposed method allows for the independent discretization of the outer surface of the object and the interfaces of different materials within it, thus enabling the generation of quasi-nonconformal meshes. This provides superior flexibility during preprocessing, especially when handling interfaces connected to the junctions. At the junctions, where more than two material regions meet, there are quasi-nonconformal boundaries between the meshes, and these quasi-nonconformal meshes are then connected in the form of MB-RWG functions. Due to the natural, normal continuity of MB-RWG, no continuity requirements or special treatments need to be imposed at these junctions. Numerical experiments are given to demonstrate the feasibility and versatility of the proposed method.