Review and application of the theory of characteristic modes for open radiating structures

Characteristic modes (CMs) are current modes obtained numerically for arbitrarily shaped conducting or dielectric bodies. These modes present really appealing properties, as they not only make possible a modal analysis of conducting/dielectric objects, but they also provide physical interpretation of the radiation phenomena and the fundamental working principle of open radiating structures. In this work, the CMs of a metallic sphere and a circular disk are related with classical TE and TM current modes. A brief review of the most recent applications of CMs to antenna design is also provided, showing the potential of this Theory to assist the design process in a great variety of applications.