  Radar beam broadening provides continuous coverage of a wider angular extent.
While many methods have been published that address beam broadening of
traditional (nonsubarrayed) arrays, there is a knowledge gap in the published
literature with respect to efficient and effective beam broadening of
contiguous uniform subarrayed arrays. This paper presents efficient and
effective methods for beam broadening of contiguous uniform subarrayed arrays
where elements of the array are grouped together to have the same element
excitations. Particularly, this paper 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. This paper presents three
metaheuristic global optimization techniques that efficiently and effectively
search for optimal phase values in this large solution space that satisfy the
desired broadened pattern. The techniques presented in this paper are simulated
annealing, genetic algorithm with elitism, and particle swarm optimization.
These techniques are evaluated on idealized 40x40 and 80x80 element rectangular
arrays with 5x5 element subarrays. The results of this study show that as
configured in this paper the simulated annealing and particle swarm techniques
outshine the genetic algorithm technique for 40x40 and 80x80 rectangular arrays
grouped into contiguous uniform 5x5 element subarrays.
