From antenna design to feeding design: A review of characteristic modes for radiation problems (invited paper)

This paper briefly reviews the recent progress of characteristic modes (CMs) for radiation problems made in the Temasek Laboratories at National University of Singapore (TL @ NUS). Unique features of the CMs offer great flexibility for the design of high performance antennas. Based on our newly developed in-house software tools for modeling CMs for 3D EM structures and N-port networks, the applications we considered include reactively controlled antenna arrays, circularly polarized antennas, platform integrated antennas, and resonant frequency characterization of microstrip antennas. Effective use of CMs can be great help in many antenna designs through proper feeding designs for an existing radiating aperture. This proposed design concept will provide an alternative to change the conventional process of antenna designs, and is also what the CM theory can really benefit the antenna community.