基于镜像综合孔径微波辐射计的二维周期型漏波天线研究

The accurate prediction of the extreme climate is very urgent to all the countries due to the enormous destructions of the unexpected meteorological disasters. The key problem is how to achieve the high spatial resolution of the remote sensing of atmospheric temperature and humidity in geostationary orbit. Due to the disadvantages of the real aperture radiometer and the synthetic aperture radiometer, there is no effective method to solve the problem of the high spatial resolution in the geostationary orbit. The mirrored aperture synthesis radiometry is an optional technological scheme, but it can hardly be realized due to the oversize mirror plane. The project is indicated to the requirement of modifying the antenna of the mirrored aperture synthesis microwave radiometer. A new research route is proposed by introducing the Bull’s eye 2-D periodic leaky wave antenna, which miniaturizes the size of the mirror plane utilizing the hollow cone radiation pattern. The high spatial resolution is supplied through optimizing the radiation characteristic parameters. The effections of the polarizations on the image retrieval, the operational behaviors of the antenna modes and the open stop-band problems will be studied. The key problems will be investigated to guide the antenna design, such as the relationship between the behaviors of the operational modes of the 2-D periodic leaky wave antennas and the environmental parameters, and the relationship between the open stop-band phenomenon and the dimension of the period. The proposed scheme provides a new antenna plan for the mirrored aperture synthesis microwave radiometer, and also supplies a new way for the high spatial resolution of the atmosphere remote sensing in geostationary orbit.

突发性气象灾害的巨大破坏性使各国都对极端气候的准确预报提出了迫切需求。重点涉及在地球静止轨道实现对大气温度和湿度的高空间分辨遥感问题。受限于实孔径和综合孔径微波辐射计各自的技术瓶颈，目前在地球静止轨道未有能有效解决空间分辨率问题的测量方法。镜像综合孔径辐射测量方法是一条可选技术方案，却因镜面尺寸过大难以物理实现。本项目针对镜像综合孔径微波辐射计对天线的改进要求，提出采用Bull’s eye二维周期型漏波天线的研究思路。其核心思想是利用空心锥形方向图减小镜面尺寸，通过优化辐射特征参数获得高空间分辨率。项目将从极化对成像影响，天线模式工作状态，开阻带问题三个方面对天线辐射机理进行研究，解决二维周期型漏波天线工作模式与环境参数之间的关系，开阻带现象和周期尺寸之间的关系等关键问题，指导天线设计。为镜像综合孔径微波辐射计提供一种新的天线方案，进而为地球静止轨道大气高分辨率微波遥感的研究和应用。

项目基于镜像综合孔径微波辐射计天线设备的需求，探索了极化对镜像综合孔径微波辐射计成像分辨率的影响，研究了一维周期型漏波天线和二维周期型漏波天线空间谐波模式的激励，传播和辐射条件。提出通过优化辐射孔径获得增益高稳定性周期型漏波天线的方法。通过开槽和加载销钉，加载寄生贴片和加载具有销钉的寄生金属条带的方式，设计了三个具有高稳定性增益的一维周期型漏波天线，在天线主波束扫描范围内均能获得小于1dB的增益波动。项目提出了利用旋转直角三角形微带贴片设计圆极化周期型漏波天线的简易方法，并且设计了两个左旋圆极化周期型漏波天线。最后项目利用理论分析结果和提出的优化方法，基于二维周期型圆形贴片阵列和bull’s eye结构，设计并优化了一款四波束二维周期型漏波天线，该天线能在35GHz工作频率附近获得13dBi左右的增益，满足镜像综合孔径微波辐射计天线设备的需求。项目对一维和二维漏波模式的工作机理进行了研究，且成果具有工程实践意义，提出的多款漏波天线具有应用于各种探测系统的潜力。