A Simplified 2-D Ray Tracing Method for Modeling Radio Wave Coverage in Tunnel Environment

In this paper, the simplified 2-D ray tracing method is put forward. The shooting and bouncing rays which is the basic theory of ray tracing method is introduced. By using the shooting and bouncing rays, the amplitude of rays can be calculated by tracing the variation of amplitude after reflection. Then two tunnels with different cross sections are considered. The radio wave coverage in the tunnels is calculated by 2-D ray tracing method and FDTD method. The results of two different methods are very close for most points. Then the field distribution on the cross section is calculated by FDTD. The results show that the reflection plane in FDTD is rough because of zigzag line at the edge of tunnel, which reveals the difference between two methods.