Antenna Positioning for Bandwidth Optimization Using Characteristic Mode Analysis

Characteristic mode analysis is used to understand the modal behavior of antennas, and how they interact with the structure they are mounted on. While this insight can be applied in various ways to improve the design, one of the biggest challenges is often how to place the antenna on the structure to excite specific mode(s). Previous work describes a good approach but imposed certain limitations multiple antennas were used, and a narrow frequency band was considered. For many applications an approach is needed to position a single antenna that operates in a wider frequency band. This paper will attempt to broaden the understanding of those limitations and proposes a design approach which surpasses the limitations, albeit at the cost of exciting additional modes. The approach covers positioning a single wider band antenna to excite specific modes while optimizing the antenna bandwidth. It is applied to two antenna examples. The bandwidth from the approach is verified using optimization.