摘要
根据随机介质中电波传播理论,应用等效介电常数法和Mie理论,研究毫米波在沙尘暴中传播的衰减;并应用Monte Carlo方法,研究沙尘暴大气中毫米波多重散射对衰减的影响。分别得到了单次散射和多重散射时沙尘暴引起的毫米波段几个大气窗口频率的特征衰减,及随沙尘大气能见度和沙尘粒子水含量的变化关系。结果表明,当能见度小于1 km时,随着能见度的减小,特征衰减增大很快,多重散射的影响也愈来愈大。衰减随含水量的增加而增加,尤其当沙尘粒子水含量大于1%时增加较为显著。因此,对于预测自然沙尘暴大气对毫米波的衰减,当能见度小于1km时,必须考虑粒子的多重散射效应。当沙尘粒子的水含量超过1%时,需要考虑水含量的影响。这些研究对民用和军用通信、遥感等系统的开发和应用均具有重要的实际意义。
Based on electromagnetic wave propagation theory in discrete random media, the millimeter wave attenuation induced by sand and dust storm is calculated by application of effective permittivity method and Mie theory. The influence of the multiple scattering on the attenuation for millimeter wave propagation in sand and dust storm is studied by Monte-Carlo method. The relations of the specify attenuation with visibility and with water content are obtained for several atmosphere window frequencies at millimeter wave band, under single and multiple scattering conditions, respectively. The results show that under visibility less than 1 km the specify attenuation and the effect of multiple scattering on attenuation quickly increase with visibility decrease, and as water content more than 1%, attenuation increases obviously with water content increase. Hence, under visibility less than 1 km, the influence of multiple scattering on attenuation must be considered for the prediction attenuation of millimeter wave propagation in sand and dust storm. Under the water content in sand particle more than 1%, the influence of the water content on attenuation must also be considered. This research is important for developing the millimeter communication, remote-sensing and so on system in civil and military applied to desert region.
出处
《电波科学学报》
EI
CSCD
北大核心
2008年第3期530-533,579,共5页
Chinese Journal of Radio Science
关键词
毫米波
沙尘暴
多重散射
衰减
millimeter wave
sand and dust storm
multiple scattering
attenuation
