【作者】 龚冰；

【导师】 李兴国； 娄国伟；

【作者基本信息】 南京理工大学 ， 信息与通信工程， 2011， 博士

【摘要】 毫米波被动探测技术在天文、遥感、军事等领域具有重要的实用价值和广阔的应用前景。随着应用的不断深入,探测系统的研究正向着更高频率的波段——亚毫米波波段的方向发展。为了研制相应的被动探测系统,本文对0.3mm～3mm波段的目标辐射特性及其辐射能量探测进行研究。由于被动探测系统接收到的辐射能量主要包括物体自身辐射的能量和反射环境的能量两部分,而且辐射能量在大气传输过程中会受到大气分子或水凝体(如雨滴)的影响,所以在分析辐射能量探测之前,须对目标辐射特性及其大气传输情况进行研究。因此,本文的研究分为物体辐射理论、辐射能量大气传输、目标辐射特性建模和辐射能量探测四个方面。在物体辐射理论方面,根据Planck方程在0.3mm～3mm波段内对Rayleigh公式进行修正。同时,介绍和分析不同分界面的发射率和反射率的计算方法,以及几种常见的金属和非金属物体的辐射特性差异。在辐射能量大气传输方面,首先对散射理论以及太气分子和水凝体的物理特征进行分析。然后利用水凝体的吸收、散射特性,对0.3mm～3mm波段降雨(或云雾等)引起的衰减进行研究,并给出衰减系数(或衰减截面)和频率的关系曲线。在目标辐射特性建模方面,首先研究兼顾天气因素的天空温度计算方法,并对目标辐射温度受物理温度影响的情况进行分析,推导出变温物体辐射温度计算模型——VTRT模型。然后通过实验测试对该模型及其参数进行验证,并利用VTRT模型对某车辆缩比模型的辐射温度分布进行仿真和预测。在辐射能量探测方面,首先基于目标辐射特性及其大气传输特性,对辐射能量的探测方式及影响因素进行分析,推导出兼顾大气衰减的辐射计探测距离计算方法。然后,进行360GHz交流全功率辐射计的方案设计,并研究相关部件的设计和选择。总之,本文从辐射能量的产生、传输和接收的角度,对0.3mm～3mm波段的目标辐射特性和探测技术进行系统地分析和研究,为该波段被动探测系统的研制提供相应的理论和技术支持。更多还原

【Abstract】 The millimeter wave (MMW) passive detection technology is applied in many fields, such as astronomy, remote sensing, military affairs and so on, owing to important practicality and wide potential application. With the application, the research on detection system advances towards higher frequency band, i.e. submillimeter wave (SMMW) band. For the developing of passive detection system of relevant band, the objects radiation characteristics and energy detection in 0.3mm-3mm waveband are studied in the paper.The radiation energy received by detectors includes the energy radiated by objects and reflected from the environment. And the radiation energy transmitted in the atmosphere may be affected by the atmosphere molecules or the hydrometeor, such as rain drops. It’s important to analyze objects radiation and atmosphere transmission characteristic before the research on radiation energy detection. So the paper mainly includes four aspects, i.e. objects radiation theories, radiation energy transmission in the atmosphere, objects radiation characteristic modeling and radiation energy detection.On the objects radiation theories aspect, Rayleigh formula is amended based on Planck equation in 0.3mm-3mm waveband. The emissivity and reflectivity of different interfaces are studied. And the differences of radiation characteristic between some normal metal and nonmetal objects are analyzed.On the radiation energy transmission in the atmosphere aspect, the scattering theory and physical characteristic of atmosphere molecules or hydrometeor are analyzed. Based on the absorption and scattering properties of hydrometeor, the attenuation caused by rain drops or else particles in 0.3mm-3mm waveband is studied. The relationship curves of frequency and attenuation coefficient or cross-section are put forward.On the objects radiation characteristic modeling aspect, the calculation method of sky radiation temperature is studied which counts on weather fact. The relationship of physical temperature and radiation temperature is analyzed. Then the vary temperature objects radiation temperature model, i.e. VTRT model, is introduced. Its rationality is validated by the experiment. At the same time, the radiation temperature distribution of a scaled vehicle model is simulated and forecasted by VTRT model.On the radiation energy detection aspect, based on the research of objects radiation and transmission characteristic, the energy detection mode and relevant influencing factors are analyzed. The distance equation of radiometer is amended including the atmosphere attenuation. Then the 360GHz AC total power radiometer is designed. And its relevant parts are chosen and designed.In conclusion, the objects radiation characteristics and detection technology in 0.3mm～3mm waveband roundly from radiation energy generation, transmission and detection are studied in the paper. It provides the theoretical and technical supports for the development of passive detection system in 0.3mm～3mm waveband.更多还原