Efficient Computation of Scattering from Core-Shell Particle Clusters based on Extended JMCFIE

This work presents an efficient numerical method for analyzing wave scattering from clusters of particles with arbitrary shapes and core-shell structures. The proposed method, called CSPC-JMCFIE (the core-shell particle cluster analyzed by the electric and magnetic current combined field integral equation), is based on the JMCFIE but treats each particle separately rather than the entire cluster as a whole. Integral equations relating the unknown electric and magnetic currents on each particle surface or interface are established individually. Coupling scattering between particles is fully considered by expanding equivalent currents into plane waves on Ewald spheres and translating between particles. Key aspects of the proposed method include establishing linear system matrices for each particle to reduce memory usage and computation time compared to treating the entire cluster as one object. Additionally, only adjacent surfaces within each particle are iterated to construct the linear systems rather than all surface combinations across the cluster. Numerical examples demonstrate the method's accuracy for clusters with different particle shapes, orientations, and core-shell layering. Compared to conventional approaches, CSPC-JMCFIE achieves similar accuracy while significantly reducing memory requirements and computation time, especially for large clusters. This makes the method well suited for efficient simulation of scattering from complex particle ensembles.