Antenna Analysis and Design Using Stored Energies and Physical Limitations

Sammanfattning: A method to estimate Q and QZ' of antennas from single-frequency current distributions is described. This single-frequency method and the concepts of physical bounds on antenna parameters and optimum current distributions are applied to different analysis and design situations of two-dimensional and three-dimensional radiating structures (i.e., antennas). The situations considered are: antenna optimization using a genetic algorithm and the single-frequency Q computation for single or multi-band operation, antenna placement optimization in a wireless device using physical bounds, and antenna optimization that includes QZ' in the objective function. Antenna performance is compared with physical bounds or optimum-current performance in the situations studied. The results presented in this thesis suggest that single-frequency methods may reduce the time necessary to optimize automatically, e.g., using a computer, some antenna parameters such as bandwidth. Furthermore, physical bounds and optimum current distributions are tools that provide valuable information for the processes of antenna analysis and design.