| Along with the low frequency resource increasingly crowded, the Ka-band, whichhas advantages of less interference and available bandwidth, becomes the applicationhot both at home and abroad. However, owing to the high frequency(20~40GHz) ofKa-band, the communication signals in Ka-band has the bigger attenuation, in which theinfluence of rainfall is the worst, so the paper study the rain attenuation characteristicsin Ka-band.This thesis analysis the attenuation mechanism of the electromagnetic wavepassing in different environments deeply, for example the affect of the air molecules,sandstorm and rain and so on, in which the rain attenuation is the biggest. Sum up andanalysis the rain attenuation models and forecast models, along with their characteristics,parameters, applicable condition and the correction methods of the rain attenuationmodels. In order to assess the rain attenuation in Xi'an accurately, it needs a lot ofrainfall datas and rain attenuation datas.Design and built the rain attenuation measuring system in Ka-band, including twosubsystems, the rainfall characteristics measuring system and the rain attenuationmeasuring system, and introduce the principle, experimental data, testing and record ofthe systems. Collect one whole year's rainfall datas and rain attenuation data by the rainattenuation measuring system in Ka-band, the measured datas was processed with themethods of data filtering, temperature compensation and fixing the standard level.Based on the rain attenuation's theory and measured datas, it gives the rain attenuationmodel in Xi'an area, and analysiss the parameters of the temperature, humidity andrainfall rate on the effect of the rain attenuation trend from the results, and gives the realrainfall characteristics and the rain attenuation characteristics in Xi'an area.This thesis study the rain attenuation model in Ka-band in Xi'an area by themeasured datas, which provides the valuable methods of measuring and calculating rainattenuation for studying the rain attenuation characteristics in other areas in China. |
