基于最陡下降法的森林路径损耗模型研究

Study of Radio Propagation Path Loss in a Forest Based on the Steepest Descent Method

为了给森林中基站建设提供参考,文章建立了森林中电波传播路径损耗的数学模型。运用有效并矢介电常数将总的散射体用等效连续介质替代,然后利用赫兹矢量位函数和最陡下降法,解出了当电波经过森林到达接收点的场强表达式,求出了电波经过森林后的衰减量。研究结果表明,当发射机和接收机之间的水平距离增加到一定量时,侧面波在总场中占主导地位,而在这之前透射波和多次反射波在总场中占主导地位。文章给出了不同工作频率和不同水平距离情况下的传输损耗的计算结果。

In order to provide a reference to the construction of base station in the forest,the propagation path loss model is built on the basis of the relationship of propagation constant and attenuation constant.The ensemble of discrete scatterers is replaced by an equivalent continuous medium described by an effective dyadic permittivity.The expression of electromagnetic is derived by using the saddle point method,Hertz vector potential function and boundary condition.When the horizontal distance between the transmitter and the receiver increases to a certain amount,the lateral waves play a dominant role in the total field.When the distance is under this amount,however,the transmitted wave and multiple reflected waves are dominant.Computation result is given of the transmission attenuation under different operating frequency and different horizontal distance.