中文摘要：

稀疏天线阵列设计是综合孔径微波辐射计的一个重要研究内容。圆环阵因其可实现（u，v）平面基线矢蜡零冗余、结构简单以及共形、波束旋转对称等特点而备受关注。针对均匀圆环阵（UCA）基线长度（基线矢量的模）冗余量大的问题，提出了两种稀疏优化方法：一种是基于受限差集的半圆环阵稀疏方法；一种是基于循环差集的全圆环阵稀疏方法。这两种方法均可大大减少阵元数，节约硬件成本；且均可解析地求出稀疏阵元位置，运算量极小，适于任意大阵元数的圆环阵稀疏优化。通过阵列旋转和分时测量，这两种圆环稀疏阵可获得与UCA相同的空间频率采样。

英文摘要：

Sparse antenna array design is of great importance in aperture synthesis radiometers （ASR）. For non-re- dundant baseline distribution and the simplicity of mechanical structure and instrumental manufacture, the circular array, as a promising configuration of ASR, has received more and more attention. Two methods for optimal thinned circular arrays are proposed to achieve the least redundancy in baseline length （ modulus of baseline vector）. One is half-circle thinning based on restricted difference set （RDS） , the other is full-circle thinning based on cyclic difference set （CDS）. Both methods can greatly reduce the numbers of the elements and channels and provide analytical solutions for the element positions of thinned circular arrays. With the rotation of the array and time-shared measurement, the thinned circular arrays resulting for both methods can obtain the same spatial frequency coverage as that of UCA.