干涉式微波成像仪地面实验系统天线阵列设计

为提出二维干涉式微波成像仪的可行方案,通过地面实验,开展利用二维合成孔径技术直接成像的研究,验证部分相关和二维成像机理及算法,检验系统的空间分辨率和温度分辨率,具有重要的科学意义。本文对二维干涉式微波成像仪地面实验系统的天线阵列进行了稀疏孔径设计。设计目标是:考虑方案的物理可实现性,即平台应用中的工程技术约束条件,在能够得到同样的空间频域覆盖的情况下,采用尽量少的干涉天线单元。理论分析和数值模拟结果表明,设计后的天线阵列满足了地面实验系统工程设计要求;设计后,6单元阵列实现了零冗余,7单元阵列冗余度仅为9.1%;空间频域的采样点对空间频域覆盖的完备性良好,为有效地进行亮温图像反演提供了可靠的可见度函数。

Antenna Array Design for the Ground-based Experimental System for Interferometric Microwave Radiometer Imager

The ground-based experimental system for the interferometric passive microwave imager is designed to test its two-dimensional part correlation, imaging mechanism and algorithm. High spatial resolution is obtained by synthesis aperture technique. One measurement is required for one spatial frequency because the object locates in the far field of antennas of the experimental system. Moreover, the antenna array is revolving during the measurement. Therefore, a sparse aperture design is desirable for the antenna array in order to reduce cost and complexity of the whole system. This paper presents a sparse aperture design for the antenna array in the ground-based experimental system. The design objective is to use as few as possible antenna elements to obtain a similar covering of the spatial frequency domain. The numerical simulation results indicate that the engineering design requirements can be satisfied. Zero redundancy is realized for an array with 6 elements. The redundancy of an array with 7 elements is 9.1%. Moreover, sampling points of the designed antenna array cover completely the spatial frequency domain. Therefore, reliable visibility functions can be provided for brightness temperature image reversion.