Particle Swarm Optimization (PSO) is a robust stochastic evolutionary computation technique based on the movement and intelligence of swarm, which is very easy to understand and implement. In order to overcome the drawbacks of standard PSO, some improved mechanisms based on the design of a novel formula for velocity updating, and global best perturbation are adopted. The simulation results of sidelobe reduction of 2-D array show that it is effective.

A new reflector shaping technique to improve the beam scanning capability of hybrid antennas (i.e. a reflector system illuminated by a phased array) is presented. Errors between the desired scan directions and the outgoing rays' directions in the scanning range are minimized by adjusting the reflector shape. This technique can be used to decrease the active element number of the feed array during the antenna scans, or reduce the gain loss caused by beam scanning when the number of active elements is given. An offset reflector antenna system is designed and analyzed, through which the validity of the technique given in this paper is demonstrated.