Characteristic Mode Analysis for Internal Resonance of Dielectric-Loaded PEC Cavity

It has been demonstrated that the information of both internal and external resonances can be acquired by using characteristic modes (CMs). However, there is limited research on CMs specifically related to internal resonances. Furthermore, existing studies on internal resonance related CMs have only focused on pure PEC cavities. In this paper, based on the concept of substructure CM, we demonstrate that CMs can also be used to explore the internal resonances of dielectric-loaded PEC cavities.