水凝物对THz波辐射的衰减研究

文章基于水凝物粒子尺寸与THz波长的大小关系，分别利用Rayleigh近似、Mie理论以及几何光学方法计算了降雨和云雾引起THz波辐射的散射衰减。比较了不同强度的降雨和不同能见度、含水量的云雾对THz波的散射衰减。结果表明，随着频率的增大，THz波段雨衰减先增大后减小；在整个THz波段，含水量较小或能见度较低的云雾的衰减随频率的增大而单调增加，含水量较大或能见度较大的云雾的衰减随频率先增大后减小；在THz波段云雾衰减随能见度的减小和含水量的增加而增大，温度对THz波段的云雾衰减影响不大，在整个THz波段并不存在明显的规律。在THz波频率高端云雾影响较降雨要严重的多。

Study on the Attenuation of Terahertz-wave Radiation Due to Hydrometeors

Based on the relation between size of the hydrometeors and the wavelength of THz, the attenuation due to rain and fog is obtained in THz band by Rayleigh absorption approximation, Mie theory and geometrical-optics approximation. The results are compared with different rain rate, water content and visibility. The results show that attenuation of rain and fog with same water content or visibility varied non-monotonically with frequency increases. The attenuation of fog with low or moderate water content and large visibility is increases monotonically, while, it is decrease in high band with large water con- tent and small visibility. The attenuation is increases as the water content increases or as the visibility decreases. The attenu- ation due to fog in high end of THz band is larger than that of the rain. Meanwhile, the effect of temperature is not significant during the range fog can presence and has no regular pattern in the THz band.