Several beamforming techniques exist. For example, in [7, 8]
tapering window is used to reduce the sidelobe level in UCCA, but
reduction in the sidelobe level increases the beamwidth. Recently,
search algorithms, such as genetic algorithms (GAs) [9] and Particle
Swarm Optimization (PSO) [10], have been used in array pattern
synthesis. GA has been used in [11] to optimize the interelement
spacing and number of elements in each ring. The thinning and
synthesis of pencil beam pattern with minimum sidelobe based on
PSO have been discussed in [12, 13]. Some studies have been devoted to
compare between the GA and PSO [14, 15] and a general conclusion has
been reached. The PSO shows better performance due to its greater
implementation simplicity and minor computational time.