Controlling radiation patterns of antennas mounted on complex platforms using the characteristic basis functions (CBFs)

A novel approach for controlling the radiation patterns of antenna systems located on a complex platform is proposed in this paper. The proposed technique takes a cue from the traditional characteristic basis functions method and starts with the generation of characteristic basis functions (CBFs) by exciting a number of antenna elements on the platform. In order to account for the design constraints into consideration, the antennas are only placed at “allowable” locations (typically specified by the user). The CBFs are generated for the complex structure under analysis by using a suitable full-wave solver. Moreover, the antenna elements need not to be identical, and different types of antennas can be used at different locations on the platform depending on the application. A singular value decomposition can be employed to remove the redundancy of the CBFs, if necessary. Next, the corresponding characteristic basis function patterns are derived and used as basis functions in the “pattern space” to realize the desired radiation pattern. Rather than using a nonlinear optimization procedure to realize the desired pattern, the pattern design process is transformed into an eigenvalue problem – which is numerical considerably more efficient to solve – to find the best-fit solution that maximizes the energy radiated in the desired angular range, while minimizing the undesired radiation outside of this range.