圆形阵列天线方向图的分布函数优化方法

以离散有限长复指数和的计算为基础,讨论了二雏阵列的方向图问题.通过引入分布函数的概念,可知离散有限长复指数和为其分布函数离散傅里叶变换在1点的值.基于此结论,分析了二维阵天线阵元分布于天线方向图之间的关系:二雏阵列任意方向的方向图为其在该方向分布函数的离散傅里叶变换,该分布函数可通过统计其投影在该方向的临近区域处阵元数目获得.然后,通过对混合圆形阵列天线方向图的分析,验证了该关系的正确性,并说明了上述关系在分析阵列方向图的应用.在此基础上,进一步分析了阵元权重系数对方向的影响,发现该方法与通过改变阵列天线阵元分布的方法等效.最后,提出了基于分布函数的圆形阵列方向图优化方法,并通过仿真实验验证了该方法的可行性.该方法可通过改变圆形阵列阵元沿径向的权重系数使得其对应的任意方向的方向图与期望的窗函数近似.

Research of Density Function Optimization Method for Circular Array Patterns

This paper discusses the radiation pattern of 2-D circular array according to t he calculation of exponential sum of finit e discrete time function. By introducing the density function, it is demonstrat ed that the value of an exponential sum of finite discrete time function is equ al to that of the discrete Fourier transform of its density function at point 1. Based on this conclusion, an approach to analyse the radiation pattern of 2-D ar ray using density function is presented, and it is shown that the directional ra diat ion pattern of a 2-D array is the Fourier transform of its density function in t he corresponding direction. Then the radiation patterns of hybrid 2-D circular a rrays are discussed to demonstrate the validity and application of this approach . Then, the effect of positive weight coefficient on the radiation pattern is di scussed, and it is found that the effect of positive weight coefficient is equiv alen ce to the distribution of elements. Finally, a weigh optimization method for cir cular array is presented, which ensures the optimized PSF similar to the Fourier transform of the desired window function approximately by adjusting the weight c oefficients.