SUMMARY
Characteristic mode analysis (CMA) can be used in antenna designs to solve radiation problems. This review focuses on the existing development methodologies for circularly polarized (CP) antennas and their axial ratio bandwidth (ARBW) improvement using CMA. To discuss the physical insights related to CP radiation, this study systematically examines different antenna design structures used in previous research. It investigates the impact of modal parameters such as the eigenvalue, modal significance (MS), characteristic angle (CA), surface current, far-field radiation behavior on CP radiation, and ARBW for various antenna designs. In addition, it discusses the comparative analysis of various antenna design approaches in terms of antenna performance parameters such as the operating frequency band, ARBW, and gain. The results show that CMA provides more valuable information for the selection of feed position in antenna designs than the conventional full-wave simulation approach.