Characteristic Mode Analysis: Application to Electromagnetic Radiation, Scattering, and Coupling Problems

Recent years, the theory of characteristic modes has emerged as a powerful analysis technique in antenna engineering, providing a means to reveal the natural resonant properties of objects and providing a variety of modal parameters. Based on these modal parameters, advanced techniques have been developed based on the theory of characteristic modes to address a wide range of electromagnetic radiation, scattering, and coupling problems. This review provides an overview of some of the latest characteristic mode-based techniques for wideband design, circular polarization, radiation pattern control, scattering control, and mutual coupling control. In addition, future perspectives are discussed, highlighting the potential of characteristic modes for addressing even more complex electromagnetics problems.