Genetic algorithm optimization of cylindrical reflectors for aperture-coupled patch elements

We investigate the application of the genetic algorithm (GA) to the design of a cylindrical reflector for an aperture coupled patch element. The goal is a certain radiation pattern defined for both polarizations. The element and the reflector together form a sector antenna. The design of such antennas is of considerable interest since sector antennas with a half-power azimuth beamwidth in the range of 30/spl deg/-120/spl deg/ constitute the majority of the base station antennas used in mobile communication systems today. Since base station antennas normally consist of linear arrays in order to focus the radiation to the horizontal plane, we only regard the azimuth pattern in this paper. There is a growing interest in polarization diversity with a focus on the design of dual /spl plusmn/45/spl deg/ polarized antennas. The key aspect of such antennas for good diversity performance has been shown to be equal response to vertical and horizontal field components, i.e. similar radiation patterns in the two polarizations.