针对传统稀疏孔径均匀圆周阵列的调制传递函数在截止频率区域内易出现零值而影响成像质量的问题,提出一种由两个均匀圆周阵列嵌套构成的无冗余的双圆周稀疏孔径结构。给出该阵列的光瞳函数以及调制传递函数的解析表达式。以5-3结构的双圆周阵列为例,以实际空间截止频率为像质评价准则,从子孔径直径、内环圆周半径以及内环旋转角度等几个方面详细分析了双圆周阵列的成像特性,给出不同情况下的实际截止频率值,并对双圆周阵列稀疏孔径系统进行模拟成像和图像复原。将该结构与均匀圆周阵列,Cornwell优化圆周阵列进行比较。结果表明,相同条件下,该阵列具有更大的实际空间截止频率,并且成像质量随着填充因子的减小而逐渐下降。

A new non-redundant double-circle sparse aperture array configuration,which is composed of two uniform circle arrays,is proposed,since the modulation transfer function (MTF) of the common uniform circle array usually has zero-value regions within the cut-off spatial frequency,which prejudice the image quality. The pupil function and MTF have been given. Taking the five-three double circles array as an example,image performance is discussed in terms of the sub-aperture diameter,inner circle radius and inner circle rotation,based on the practical cut-off frequency. Imaging simulation and image restoration are given. The results show that,compared with the uniform circle array and Cornwell′s optimized circle array,the double circle array has higher practical cut-off frequency,and the image quality degrades with the decrease of filling factor.