Fast Analysis of Characteristic Modes Using Hybrid Integral Equation Methods

To expedite the characteristic mode analysis (CMA) of electromagnetic target structures, this paper combines frequency- and material-independent reactions (FMIR) with characteristic mode analysis using the volume-surface integral equation (VSIE). Although the CMA based on VSIE is not affected by spurious modes when calculating targets containing dielectric, its matrix is high dimensional, resulting in slower calculations. FMIR only needs to store the calculation once for matrices that are independent of frequency and material parameters, which greatly reduces the repetitive operations when calculating multi-frequency impedance matrices. Numerical results show that combining FMIR with the CMA using VSIE can effectively improve the computational speed.