This paper presents a novel approach for computing substructure characteristic modes. This method leverages electromagnetic scattering matrices and spherical wave expansion to directly decompose electromagnetic fields. Unlike conventional methods that rely on the impedance matrix generated by the method of moments (MoM), our technique simplifies the problem into a small-scale ordinary eigenvalue problem, improving numerical dynamics and computational efficiency. We have developed analytical substructure characteristic mode solutions for a scenario involving two spheres, which can serve as benchmarks for evaluating other numerical solvers. A key advantage of our method is its independence from specific MoM frameworks, allowing for the use of various numerical methods. This flexibility paves the way for substructure characteristic mode decomposition to become a universal frequency technique.

翻译：本文提出了一种计算子结构特征模的新方法。该方法利用电磁散射矩阵和球面波展开直接分解电磁场。与依赖矩量法生成的阻抗矩阵的传统方法不同，我们的技术将问题简化为小规模常特征值问题，从而改善了数值动态范围并提高了计算效率。我们针对双球体场景开发了解析子结构特征模解，可作为评估其他数值求解器的基准。本方法的一个关键优势在于其独立于特定矩量法框架，允许使用各种数值方法。这种灵活性为子结构特征模分解成为通用频率技术铺平了道路。