中文说明：
该文件是模拟电磁波传播过程中遇到障碍物遮挡使信号与接收装置之间不能直视而产生的传输误差，对模拟电磁波传播具有很大帮助。
English Description：
This file is the transmission error caused by obstacles in the process of simulating electromagnetic wave propagation, which makes the signal and the receiving device can not be directly viewed, which is of great help to the simulation of electromagnetic wave propagation.