Pattern synthesis of planar arrays using genetic algorithms

Phased arrays offer possibilities of having multifunctional radar on a carrier such as an aircraft, etc. large uniform planar arrays require a large number of antennas and occupy a large area on the platform and is thus expensive in terms of hardware. Increasing the inter-element spacing to reduce the hardware requirement gives rise to grating lobes in the radiation pattern. Optimizing the inter-element spacing for a maximum main-lobe-to-average sidelobe ratio results in an uniform array. Minimizing the number of antennas and utilizing the available space on the platform is the topic of this paper. This paper presents a method that allows the antenna elements to be distributed in a given space without degrading the radiation pattern. It uses genetic algorithms to optimize complex weights for each of the elements and thin the array for maximum main-lobe-to-average sidelobe ratio. The results are compared to that for a uniform planar array. The method is extended to antenna distribution in an irregular space such as an irregular polygon which results in deteriorated resolution and main beam regularity.