Synthesis of thinned planar circular array antennas using biogeography based optimization

This paper presents a novel optimization algorithm biogeography based optimization (BBO) for thinning large multiple concentric circular ring arrays. The objective is to achieve an array of uniformly excited isotropic antennas that will generate a narrow beamwidth and minimum relative side lobe level (SLL). BBO is a new comprehensive force based on the science of biogeography. Biogeography is the schoolwork of geographical allotment of biological organisms. BBO utilizes migration operator to share information between the problem solutions. The problem solutions are known as islands and sharing of features is called migration. In this paper, the authors propose pattern synthesis method to reduce the SLL with narrow first null beamwidth (FNBW) by making the ring array thinned using the BBO algorithm. In this paper a nine ringed concentric circular antenna array with central element feeding is considered. The computational results show that the number of antenna array elements can be brought down from 279 to 131 with simultaneous reduction in SLL of more than 21 dB with a fixed FNBW.