对称指数分布的子阵级多波束形成方法

Subarray multibeamforming with symmetric exponentially spaced array

为实现子阵级多波束和避免由于子阵相位中心均匀稀布带来的栅瓣问题,提出了基于对称指数分布的子阵相位中心优化方法和非均匀子阵级窗函数。在阵列孔径和阵元个数给定的情况下,提出了选取合适指数参数r的步骤并用于子阵等效相位中心设计,根据子阵中心推导了非均匀泰勒窗函数,最后用多指向的加窗空域匹配权实现子阵级数字多波束。仿真结果显示,基于优化子阵中心并采用推导的非均匀加权的线阵具有无栅瓣、近区低旁瓣、阵列效率损失小等优点;应用于对称阵子组成的线阵,获得的方向图与数值电磁代码软件计算的结果吻合;推广到对称指数分布面阵同样具有有效性。

An optimized method for the phase centres of subarray based on the symmetric exponentially distribution and a nonuniform window of the subarray are proposed to realize the subarray multibeamforming and avoid the grating lobe due to the uniform sparse phase centers of subarray. Firstly, given the aperture and the number of the array, the phase centers of the subarray are optimized through an approach of choosing the approatiate exponential parameter. Secondly, an nonuniform Taylor window is derived for the sidelobe control according to the optimized phase centers. Finally, the subarray multibeamforming can be achieved with the windowed steering vector pointing at the various directions. Simulation results show that the linear array with the optimized phase centers and the nonuniform window has the advantages of no grating lobe, low sidelobe level nearby the mainlohe and the high array efficiency over other methods; the pattern results of the method applied in the linear array composed of symmetric array elements agree with that of numerical electromagnetic code （NEC） software; the proposed method spreading to the plane array of symmetric exponentially distribution is also available.