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摘要5mm波段处于毫米波非大气窗口频段，在大气中传播时受不同大气条件的影响，电波传输由于吸收和散射产生衰减。本文研究了5mm波段受大气中氧气分子和水蒸气分子的吸收效应以及云雾、降雨、降雪和沙尘的吸收和散射对毫米波传播产生的衰减。根据适当的模型对各种条件下的5mm波段衰减进行讨论，与相关文献实测数据对比，本论文仿真获得结果接近实测值。首先，根据MPM模型仿真了晴空条件下毫米波的传播特性，明确了60GHz氧气吸收带；其次，以云雾、降雨、降雪以及沙尘产生的衰减为主要因素，分析了其对毫米波的吸收和散射作用。得出结论：云雾、降雪和沙尘条件下，含水量越大，对毫米波产生的衰减率值也越大；降雨条件下，降雨率越大对毫米波传输产生的衰减率越大。降雪和沙尘除了水分吸收作用，还会由于散射产生衰减，但是5mm波段波长相对微粒尺寸较大，散射衰减率将不会很大。当多种气象条件同时存在时，我们也必须同时考虑多种衰减同时存在。关键词 5mm 毫米波 衰减 MPM模型 MP模型毕业设计说明书（论文）外文摘要8503
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Title Research on the atmospheric propagation characteristics of 5mm waveband
Abstract
5mm waveband is the non-atmospheric window waveband, when propagating in atmosphere, it is attenuated for absorption and scattering of different atmospheric condition. In this paper, the attenuation of 5mm waveband caused by the absorption of oxygen and water, cloud, rain, snow and dust, is researched. According to appropriate model , the attenuated of 5mm waveband is researched under a variety of conditions. And comparing to the measured data from the related literature, the simulation result in this paper is closed to the measured data. First, based on the MPM model, the propagation characteristics of millimeter-wave is researched and simulate in the condition of clear sky, and then 60GHz oxygen absorption is verified. Second, considering clouds, rain, snow and dust as the main factors which cause the attenuation,the absorption and scattering effect of millimeter-wave caused by them are researched. In the end it comes to the conclusion that in the condition of clouds, snow and dust, the rate of attenuation is proportional to the water content; And in the condition of rain, the more the water content is , the greater the attenuation is caused. The condition of snow and dust not only has the effect of the absorption of water, but also generate attenuation for the reason of scattering. But the wavelength of 5mm waveband is longer compared to the particle size,so the attenuation which is generated by scattering is not greatly. A variety of attenuation must be considered when a variety of weather conditions exist at the same time.
Keywords 5mm Millimeter wave attenuation MPM MP
目 次
1绪论 1
1.1 研究背景和意义 1
1.2 毫米波传播特性的研究概况 2
1.3 论文工作安排 4
2 晴空大气衰减特性研究 6
2.1 接地面水平路径上的衰减 6
2.2 地面倾斜路径大气衰减 12
2.3 本章小结 14
3 云雾衰减特性研究 15
3.1 云的分类 15
3.2 云滴尺寸分布 16
3.3云雾衰减计算 18
3.4 五种经验公式对比 21
3.5 地——空路径云雾衰减 23
3.6 本章小结 24