Irregular Phased Array Architecture With Small Directivity Drop for Wide-Angle Scanning Application

A novel irregular phased array tiled by subarrays composed of two isolated elements (SCTIEs) is proposed in this article. At first, reasons of significant directivity drop in traditional polyomino-shaped irregular arrays in large-angle scanning scenario are investigated. To reduce the quantization errors of the excitations, the two elements in this proposed irregular array are interleaved with one element which belongs to another subarray. Second, to solve the complex double-element irregular subarray tiling problem, a new approach named Subarray Rotation Algorithm based on Monte Carlo algorithm is proposed. Since the problem is no longer regarded as a nonlinear pure integer programming problem as that in previous research but a simplified element-location transformation problem, the proposed method can dramatically reduce the optimization time to 0.07% for an array as large-scale as 36
$\times36$
. Consequently, through the two steps of array tiling generation and excitation coefficients optimization, better radiation performance is realized based on the SCTIE-shaped irregular arrays compared with conventional domino-shaped arrays. In addition, the proposed irregular array achieves stable performance in a broad frequency band and in different array scales. Finally, several numerical examples are presented to verify the proposed method.