Study On The Properties Of Rain Attenuation On Microwave And Millimeter-wave Propagation

Rain have important effects on the performance of microwave and millimeter systems operating at frequencies above 10GHz, for the proper planning of microwave and millimeter systems it is necessary to have appropriate rain attenuation prediction techniques. In this thesis, rain attenuation characteristics and prediction techniques and fade mitigation methods are reviewed systematically. The prediction methods of rain attenuation are mainly studied, and the main results obtained are the bellowing:1. According to the prediction model of rain attenuation (China model) for earth-space path submitted to ITU-R by China Research Institute of radiowave propagation in 2003, and new edition of Recommandation ITU-R P.838-3, the coefficients in China model are re-optimized. The new China model has been obtained with better prediction accuracies than ITU-R model and UK model.2. Based upon the experimental data in ITU-R database, a new prediction model of rain attenuation for the terrestrial line-of-sight systems is proposed in this paper, where the new path adjustment factor and the new conversion formula for estimating the exceeded attenuation of other percentages of an average year from the exceeded attenuation of 0.01 of an average year have been developed. Compared with ITU-R model and UK model, this model has got better agreement with the experimental data.3. A physical model of rainfall along propagation path is proposed, and based on this physical model, a new prediction model of rain attenuation for earth-space path is developed, this new prediction model of rain attenuation also show better agreement with the experimental data than ITU-R model and UK model.4. Several methods for fade countermeasurements are discussed.