弱沙尘环境中太赫兹波的散射与传输特性研究

Research of scattering and propagation characteristic of terahertz wave in weak sand dust atmosphere

基于HITRAN2012数据库,采用三次样条插值算法给出了太赫兹波段沙尘颗粒的复折射率随电磁波频率的变化曲线。采用Mie散射理论,分析了不同粒径沙尘颗粒对太赫兹波的散射及消光特性。基于单次散射假定,研究了太赫兹波在浮尘、扬沙等弱沙尘环境中的散射与传输特性,考虑不同条件下沙尘粒子的谱分布,分析了入射频率、粒径分布等因素对散射及衰减特性的影响。结果表明:在1 THz~4 THz太赫兹波段,单个沙尘粒子的散射及消光特性分布主要由粒子的尺寸参数决定。对于尺寸较小的沙尘粒子,后向散射系数随着尺寸的增加而增大。当粒子尺寸较大处于Mie振荡区时,后向散射系数起伏变化较大。在浮沉和弱沙尘两种天气条件下,沙尘粒子群的统计消光系数随着入射频率的增大具有相似的增大趋势。本文研究结果对太赫兹波技术在应急通信、大气环境监测、风沙探测等相关领域中的应用具有参考价值。

Based on the HITRAN2012 database,the variation of complex refractive index of sand dust in the terahertz bands was obtained by using the method of cubic spline interpolation.Using the Mie theory,scattering properties of sand particle with different sizes illuminated by the terahertz wave were analyzed.Propagation characteristic of terahertz wave in weak sand dust atmosphere condition was investigated,where only single scattering effect was considered due to the low volume ratio of the particles.The results show that the scattering intensity distributions of the sand particle in the range of 1 THz to 4 THz depend mainly on the size parameter of the sand particle.For small particles,the backscattering efficiency increases monotonically with the increase of the size parameter.While big oscillation was found for particle with large size parameter.In different sand atmosphere conditions characterized using different size distributions of sand dust,the statistic extinction efficiency increases as the increase of the frequency.This paper provides useful reference for the application of terahertz wave in emergence communication,atmosphere monitor,and detection of sands.