Optimization of SLL and FNBW in Linear Arrays Using PSO

In many communication applications like radar and point to point micro wave links, narrow beamwidth and low side lobe level beams are required. Trying to generate narrow beams using conventional antenna synthesis methods results in higher side lobe levels and trying to generate low side lobe beams results in broader beams. Dolph chebychev linear array method is a compromise between SLL and FNBW. In this method, for a given SLL, the narrowest beam width is obtained and for a given beamwidth the smallest SLL is obtained. But the smallest SLL for the narrowest beamwidth is not obtained. In this paper an effort is made to get the narrowest main beamwidth without significantly increasing SLL and the smallest SLL is obtained without significantly broadening the beamwidth using random stochastic methods like Particle swarm optimization (PSO) and Genetic algorithm (GA). Results obtained with PSO and results obtained with GA are compared.