||With more and more applications in the wireless internet multimedia, the importance of terrestrial microwave communication should be studied and investigated. However, most people tend to apply the frequency in Ka-band (26-40GHz) for the lack of the useful spectra. But the region of Ka-band is sensitive to be influenced by the environment, when it transferred in the atmosphere, especially for the attenuation by the rain or the vegetations. In this study, we will discuss some effects of them.|
The prediction of rain attenuation due to rain is considered the EM wave propagating through rain drops, the energy of the EM wave will be absorbed and scattered by rain drops, then the raindrop-size distribution (DSD) is the most effective part in the prediction of attenuation. Various raindrop-size distributions have been proposed in a number of recent studies. Exponential、Gamma 、Weibull、Lognormal distribution have been use to be the raindrop-size model. By applying the suitable raindrop-size distribution model, we can calculate the rain attenuation more accurately. Lin [ 14 ] analyzed the raindrop-size distribution in Chung-Li and find out the raindrop-size distribution in Chung-Li following the Gamma distribution. In this study, we consider number of Raindrop, because it will effect TCS(Total Cross Section). Our measurements of rainfall observed is using a distrometer in Chung-Li and fitting parameter N0(R), then use rain attenuation model to calculate attenuation.
In the effects of vegetations, the situation of vegetation in different wind speed is considered. We measured signals the transmission and reflection through the broadleaf -tree, and find the relation with wind speed change by statistics calculating. The results show that the probability distributions in different winds are invariable. Finally, we can just care about the path of attenuation rate through the broadleaf –tree inside.
|| Sadiku, N. O., “Numerical Techniques in Electromagnetics,”|
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