【作者】 王楠楠；

【导师】 邱景辉；

【作者基本信息】 哈尔滨工业大学 ， 电磁场与微波技术， 2007， 硕士

【摘要】 毫米波焦面阵成像系统是根据不同物体的毫米波辐射特性的不同,适当选择毫米波辐射计的工作频率、极化方式和波束入射角,通过天线收集目标、背景的毫米波辐射能量,产生反映目标、背景辐射特征的图像,从而识别不同类型的目标。毫米波焦面阵成像将电扫描与机械扫描相结合,可以解决机械扫描分辨率低,不能实时成像的缺点。提高系统的分辨率是设计毫米波成像系统的关键技术之一。本课题所研究的椭球天线不同于透镜天线、旋转抛物面天线等,它具有双焦点结构,能够将来自一点的能量聚焦于另一点。因此,可以降低对接收机灵敏度的要求,提高系统的分辨率。首先,本论文简介了黑体辐射原理及和毫米波成像的关键技术,其中包括扫描原理和采样频率的确定。并从聚焦的基本概念入手,推导了均匀辐射圆口径的菲涅尔区辐射场。利用MATLAB编制程序,绘制了不同口径相同焦距的聚焦天线以及相同口径不同焦距的聚焦天线的聚焦特性曲线,从聚焦的能量和聚焦范围方面给出了一定的规律。其次,本论文运用统计方法并编制MATLAB程序探寻椭球天线的共轭成像特性。得到了不同尺寸椭球的聚焦特性。并选择聚焦特性较好的椭球,着重分析了其偏焦特性。第三,本课题利用CST-Microwave Studio?仿真软件对椭球天线的反射损耗,方向图进行了仿真,着重用探针观测了焦面上的场强,给出了正馈及偏焦情况下其3dB焦斑的半径及聚焦的位置,并与椭球共轭成像统计计算结果进行了比较。最后,在仿真的同时,利用毫米波辐射计探测了不同物质的辐射特性,探测了金属板相对于天线不同位置时的检波电压。更多还原

【Abstract】 Millimeter-wave focal plane array imaging system is based on the difference between objects in the millimeter-wave radiation, choosing appropriate millimeter -wave radiation frequency, polarization and beam angle of incidence, through antenna collecting millimeter-wave radiation energy of target and background, generating the image of reflecting objectives and background radiation characteristics, thereby identifying different types of objectives. Millimeter-wave focal plane array imaging system will combine electric and mechanical scanning, solve the problem of low resolution using mechanical scanning and unidentified real-time imaging.One of the key technologies of millimeter-wave imaging system is improving the resolution. The ellipsoid lens antenna in this paper is different from lens antenna and rotating dish antenna, it has dual focus structure, can focus the energy from one focusing point to another focusing point. Therefore, we can reduce the sensitivity of the receiver, improve of the resolution of the imaging system.First, this paper briefly introduces the key technologies of blackbody radiation and meter-wave principle imaging, and the difference between ellipsoid antenna and traditional focusing antenna. From the basic concept of focusing, this paper calculates Fennel zone radiation field of uniform radiation round caliber. Using MATLAB, this paper draws characteristic curve of different caliber but same focal length and same caliber antenna but different focal length focusing antenna, concludes certain regularity of focusing energy and scope.Secondly, this paper uses statistical methods to study ellipsoid conjugate imaging, and uses MATLAB to obtain the results with statistical characteristics. It can approximately express its imaging law. Then this paper explores the ellipsoid focusing properties at different dimensions, and concludes certain regularity, selects better ellipsoid with focusing properties, analyzes the characteristics of its partial focusing.Finally, the paper uses CST-Microwave Studio software simulates the return loss of ellipsoidal antenna, observes field on the focusing surface using the probe, determines its focusing radius of 3 dB and the focusing position under the circumstance of feed and biased focusing, compares it with the conjugate imaging statistical results.更多还原