不同类型降水对毫米波传播特性的影响研究

为了提高复杂降水条件下毫米波传播衰减的评估精度，通过分析多个地区的降水谱特征，得出具有代表性的层状云降雨、积层混合云降雨、积雨云降雨以及干雪、湿雪的谱分布参数，然后结合降水粒子的形状、相态、介电模型，计算降水体目标在毫米波波段的散射特性.结果表明，降水强度不是唯一影响毫米波传播衰减的因素; 降水粒子相态、谱分布、入射波频率和温度等对毫米波传播特性均有不同程度的影响，其中谱分布和数密度是影响降雨对毫米波衰减的主要因素; 冰水构成比例是影响降雪对毫米波衰减的主要因素; 不同相态的降水，尤其是干雪、湿雪和雨对毫米波传播影响的差异较大; 而温度的影响较小.并建立了考虑谱分布和温度的降水衰减模型.

Effect of different precipitation on characteristics of millimeter wave propagation characteristics

To promote the evaluation precision of millimeter wave transmission attenuation in the complex precipitation condition, representative size distribution parameters for five kinds of precipitations (stratiform rain, mixed stratiform and cumulonimbus rain, cumulonimbus rain, dry snow and wet snow) were obtained by analysis of precipitation characteristics in many areas. Combined with the shape, phase and dielectric model of the precipitation particles, the scattering characteristics of precipitation particle clusters at the millimeter waveband were calculated. The numerical simulation results show that the precipitation intensity is not the only factor that influence the millimeter wave propagation characteristics; the phase of particle, drop size distribution, incidence wave frequency and temperature have different effects on the millimeter wave propagation, The size distribution and number density are the main factors influencing the millimeter wave propagation attenuated by rain. The composition of ice and water are the main factors influencing the millimeter wave propagation attenuated by snow. The phase of precipitation particles also have strong effect on the millimeter wave propagation. There are distinct differences between the snow and rain. The temperature is the least factors. At precipitation attenuation model was established based on the drop size distribution and temperature is established.