Characteristic mode analysis of electromagnetic structures

Characteristic mode analysis (CMA) is an eigenanalysis technique that is particularly useful for gaining insight into the radiating properties of arbitrary electromagnetic structures. This work reviews a numerically efficient implementation for solving the generalised eigenproblem that results from separating the Method-of-Moments (MoM) impedance matrix in its real and imaginary components. Furthermore, the approach undertaken to deal with the tracking of eigenvalues as a function of frequency is also explained. Finally, the usefulness of the CMA implementation and mode tracking approach is illustrated at the hand of an example.