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水汽凝结体对太赫兹波在大气中的传输衰减起重要作用。针对太赫兹波在云层中受到水滴和冰晶相互作用下的衰减效应进行了研究。首先构建了三维大气分层结构,显示了云层在大气中的二维分布,基于洛伦茨-米理论和Tmatrix方法分别对云层中球形水滴和非球形冰晶粒子在太赫兹波段的吸收和散射效应进行了数值计算,发展了一个太赫兹波在云层中传输的统计衰减模型。将水云的计算结果与国际无线电联盟(ITU)的结果比对验证了理论方法的有效性。分析了太赫兹波段水云和冰云的衰减特性,发现太赫兹波段冰云的散射特性明显,衰减系数平均比水云高十几d B。在倾斜路径大气分层传输模型中加入云的统计衰减模型,利用雷达测量的绵阳地区的云层分布特点,计算了太赫兹波在真实大气的传输衰减,为太赫兹波星地通信提供了重要参考数据。
Condensate vapor plays an important role in the transmission attenuation of terahertz waves in the atmosphere. The attenuation effect of terahertz wave in the clouds under the interaction of water droplets and ice crystals was studied. Firstly, a three-dimensional atmospheric layered structure was constructed, showing the two-dimensional cloud distribution in the atmosphere. Based on Lorentz-M theory and Tmatrix method, the absorption and scattering effects of spherical water droplets and non-spherical ice particles in the terahertz band Numerical calculations were carried out to develop a statistical attenuation model for the transmission of terahertz waves in the cloud. Comparing the calculation result of water cloud with that of the International Telecommunication Union (ITU), the validity of the theoretical method is verified. The attenuation characteristics of the water cloud and the ice cloud in the terahertz band are analyzed. It is found that the scattering characteristic of the ice cloud in the terahertz band is obvious, and the attenuation coefficient is on average ten days higher than that of the water cloud. By adding the statistical attenuation model of cloud to the stratospheric atmospheric transmission model, the transmission attenuation of terahertz wave in real atmosphere is calculated by using the cloud distribution in Mianyang region measured by radar, which provides an important reference for terahertz wave satellite communication data.