PSO fitness function used in antenna arrays pattern synthesis

Fitness function is important for convergence and efficiency to particle swarm optimization(PSO),especially in optimizing array antenna pattern synthesis.In order to improve performance of PSO, a multistage fitness function strategy is adopted to avoid convergence stagnation.The simulation results show its high performance in the radiation antenna arrays pattern synthesis with multi-null and low sidelobe restrictions,while there is no modification to PSO algorithm.