: In this paper, we intend to study the synthesis of the multibeam arrays. The synthesis implementation’s method for this type of arrays permits to approach the appropriated radiance’s diagram. An adaptive particle swarm optimization algorithm (APSO) is proposed to synthesis multibeam antenna arrays. The problem is formulated and solved by means of the proposed algorithm. The examples are simulated to demonstrate the effectiveness and the design flexibility of adaptive PSO in the framework of electromagnetic synthesis of linear arrays.