A Study on Electromagn etic Wave Propagation Prediction for Mobile Communication in an Urban Space

首先分析了建筑物墙体的电磁散射，因为这是预测高层建筑包围的城市区域中波传播的重要因素之一。对于裂纹散射的分析，我们可以建立基于金属表面裂纹后向散射响应的深度估计方法。其次，为了有效地分析电磁波的传播，提出了自适应射击和弹跳射线法(自适应SBR)，通过二维截面分析，详细地测试了我们的方法应该包括多少多次反射和绕射，以及需要多少样本来估计全局场分布。为了验证该方法的准确性，将结果与用时域有限差分(FDTD)方法得到的结果进行了比较。并对1.9 GHz(PHS)频段的基站信号强度进行了测试。结果表明，该方法具有较好的一致性。我们还试图寻找更高效的算法和快速的计算方法来处理更多的Karger样本数据。

Electromagnetic scattering by the building walls has been analyzed first, since this is one of the important factors for predicting the wave propagation in urban area enclosed by tall buildings. For the analysis of crack scattering, we could establish the depth estimation method from back scattering response for cracks on the metal surfaces.Next, Adaptive shooting and Bouncing Rays (Adaptive SBR) method has been proposed to analyze electromagnetic wave propagation effectively, by 2Dcross sectional analysis, our method has been tested in detail how many multiple reflections and diffractions should be included, and how many samples should be taken to estimate the global field distribution.In order to check the accuracy of the method, the results are compared with those obtained by the Finite Difference Time Domain (FDTD) Method. Test measurements are also done for signal strength from base station for 1.9GHz (PHS) band. Good agreement has been found to show the validity of our method. We have also tried to find more efficientalgorithm and fast calculation method to handle more karger sample data.