Abstract
In modern antenna systems, beam broadening of subarrayed arrays provides continuous coverage of a wide angular extent in a cost-effective manner. While many methods have been published that address beam broadening of traditional (non-subarrayed) arrays, there is a knowledge gap in the published literature with respect to efficient beam broadening of contiguous uniform subarrayed arrays. This dissertation presents efficient and effective methods for beam broadening of contiguous subarrayed arrays where elements of the array are grouped together to have the same element excitations. Particularly, this dissertation focuses on phase-only optimization to preserve maximum power output. The high dimensionality of the solution space of possible phase settings causes brute force techniques to be infeasible for exhaustively evaluating the entire space. Three metaheuristic global optimization techniques: simulated annealing (SA), genetic algorithm (GA) with elitism, and particle swarm optimization (PSO); and three modified iterative Fourier transform (IFT) methods: integrated IFT (iIFT), decoupled IFT (dIFT),and subarray spaced IFT (ssIFT) are presented to efficiently search the vast solution space of possible phase settings for a solution that effectively satisfies the desired broadened pattern. The results of this study show that satisfactory radar patterns can be obtained more efficiently by using the three modified IFT methods, but the metaheuristic global optimization techniques achieve better effectiveness at the cost of lower efficiency
