Judgment of mode crossing avoidance in characteristic mode analysis

Abstract

The consistent interpretation of modes is crucial in characteristic mode analysis, which can usually be achieved by mode tracking algorithms. However, the problem of the eigenvalue crossing avoidance is still challenging to solve completely. In this paper, the possible causes of the eigenvalue crossing avoidance are discussed, and divided into two types. According to the characteristics of the modes with the cross avoidance, a comprehensive method for locating the frequency of crossing avoidance is first proposed. Since the crossing avoidance occurs in the case of degenerate mode coupling, the decoupling method is applied to eliminate the mode cross avoidance. Finally, the method’s effectiveness is verified by dealing with crossing avoidance problems of a rectangular conductor, dipole, and skewed plate structure. The proposed method is only related to the mode number to be discussed, and its calculation is time-saving.