The thinning methods were usually used to simplify the array complexity by turning off some of the radiating elements in large planar arrays which lead to unavoidable reduction in the directivity. In this paper, an alternative method is used to simplify the array complexity by partitioning a large array into two contiguous subarrays. The first subarray is in circular planar shape in which its elements are uniformly excited, while the second subarray in which its elements surround the circular subarray, and they have significant impacts on the array radiation features and are chosen to be adaptive. The desired radiation characteristics are then obtained by optimizing only the adaptive elements which are far less than the total number of the original array elements. Since the majority of the elements in the proposed array are uniformly excited, its directivity and taper efficiency are found very close to that of the benchmark solutions. Simulation results verify the effectiveness of the proposed array.
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