Short Millimeter Wave Target Radiation Characteristics

With the development of passive detection technology, the short passive millimeter wave detection technology has also made great achievements. Both short millimeter waves provided with some good features, it also has its own unique characters. Because of this, in many areas, the short millimeter wave has a broad prospect on applications. This paper is to study the characteristics of short millimeter wave radiation, the factors affecting the transmission characteristics, analyze the distribution and the attenuation model due to the various factors and introduce the inversion temperature methods briefly.Firstly, the paper describes the theory on the radiation of electromagnetic wave and the concept of the sky temperature, followed by introduction of the impact factors of sky temperature, for example the oxygen and water vapor absorption coefficient of the model,and the simple calculation. Secondly, under the conditions of rainfall and cloud, the paper introduces the transmission of electromagnetic waves in atmospheric conditions. Describing the physical properties of rainfall and cloud, size distribution, the models of droplet spectrum of raindrop and fog, and scattering characteristics and so on, and analyzes them, briefly. And then it completes the calculation of the attenuation coefficient. Finally, the paper introduces the inversion of an apparent temperature based on the antenna temperature, and some inversion temperature methods, and the interpolation solutions by using the experimental data to achieve the temperature inversion, solving the apparent temperature.This paper attempts to study the radiation characteristics of short millimeter wave and a variety of atmospheric factors on the transmission characteristics. Based on the above study, using simulation and analysis of experimental data, we achieve the target of the apparent temperature inversion.