Fast Computation of Volume Integral Operator-Based Characteristic Modes With Skeletonization

Calculating characteristic modes of dielectric objects with the volume integral operator (VIO) is computationally inefficient. The volumetric mesh generates a large impedance matrix and results in a time-consuming eigenvalue equation-solving process. Skeletonization is employed to improve the efficiency of the VIO-based method by leveraging the rank-deficient property. Both the memory and time required for assembling impedance matrices are significantly reduced. The repeated matrix-vector multiplications involved in solving the eigenvalue equation are expedited. Numerical examples are presented to validate the accuracy and efficiency of the proposed method. Parameter optimization is performed to achieve a more practical and efficient algorithm setting.