Radiation pattern optimisation of an antenna array on the spherical surface by using a varying number of optimisation parameters

Abstract

This study presents an optimisation of antenna arrays on the spherical surface with new elementary antenna distribution using the particle swarm optimisation method. Many distributions of antenna elements on the sphere are known and processed, like icosahedral, spiral, Leopardi and so on, but neither of them is optimal. In this study, optimisation of the antenna array includes radiation pattern optimisation in order to achieve a radiation pattern with a narrow main lobe and very low side lobes. Although distribution of antenna elements is not uniform, optimisation is performed for two planes using the average fitness function. Different applications of antenna arrays require different parameters and different optimisation/process control procedures, too. Spherical antenna arrays with optimised placement of elements are capable of producing a desired radiation pattern, providing electronic scan coverage over the entire sphere and satisfying requirements for many applications in different branches of communications. An antenna array analysed in this study is a spherical array with very low grating lobes and a very narrow main lobe, and it could be used in hemispherical scan coverage.