云对通信信号传播损耗的研究--毕业设计.doc

云对通信信号传播损耗的研究 [摘要]分析了云的基本特性，讨论了云与通信信号的相互作用机理，基于Mie散射理论，数值计算了云中球形粒子对电磁信号散射的散射特征量；利用低空中的晴空大气对电磁波信号传播损耗经验公式，数值计算了并将所得结果与Mie散射计算的结果相比较，分析了两者的差异，所得结果可为正确理解电磁信号在云中的传输特性提供参考和技术支持。 [关键词]通信信号；传播损耗；散射理论；衰减 Research on the propagation attenuation of signal of communication caused by clouds Abstract: Analyzing the basic characteristics of clouds, and the interaction mechanics between clouds and signal of communication is discussed, Based on Mie scattering theory, the scattering characteristical quantity of spherical particles in clouds action with electromagnetic signal are numerical calculated. Combining with the spectral distribution function of particles in clouds and using the experiment formula of propagation attenuation of electromagnetic signal in low atmospheric with clear sky, the author numerical calculating the attenuation of electromagnetic signal caused by several common clouds. Meanwhile, based on Rayleigh scattering theory and combining with the experiment formula of attenuation coefficient of electromagnetic wave caused by clouds, the numerical results of attenuation of electromagnetic signal caused by clouds are given. The results which calculated by Mie theory and Rayleigh individually are compared and their difference is analyzed, this can provide conference and technology support for correct understand the propagation characteristics of electromagnetic signal through clouds. Key words:communication signals, propagation attenuation, scattering theory, attenuation 目 录 引言 3 1 云的形成、种类及基本特性 3 1.1云的形成 3 1.2云的种类 4 1.2云的特性 4 2 通信信号与大气粒子的相互作用 7 2.1大气分子对通信信号影响 7 2.2大气气溶胶粒子对通信信号的影响 7 2.2.1气溶胶对通信信号的散射作用 7 2.2.2气溶胶对通信信号的吸收作用 8 2.3大气湍流对通信信号的影响 8 2.3.1大气湍流的形成 8 2.3.2大气湍流对通信信号的影响 8 2.4大气对水平方向通信信号的吸收 8 2.5大气对斜路通信信号的吸收 11 2.6地空路径干湿空气的吸收 12 3 云对通信信号衰减的计算 15 3.1 相关参数的概念 15 3.2Mie散射理论下的云的衰减 18 3.2.1.Mie散射理论的特点 18 3.2.2云对电磁信号的衰减计算 20 3.3 Rayleigh散射的概念及特点 23 3.3.1Rayleigh近似理论 23 3.3.2云对电磁信号的Rayleigh近似 24 3.4两种理论下结果的比较 26 4 结语 27 致谢 27 参考文献 28 附录-外文翻译 29 引言 随着社会的进步和科学技术的飞速发展，人