Effects of structural and environmental parameters on the coupling loss of leaky rectangular waveguide in tunnel

The effects of the structural and environmental parameters on coupling loss of leaky rectangular waveguide in tunnel are studied in this paper, the parameters include the tunnel size and the slot period of leaky waveguide. A new approach based on ray tracing method is proposed for computing the distribution of coupling loss above the upside wall of the leaky waveguide. The approach is verified by comparing the results with those of available method. The results of this paper show that the average value of the coupling loss along the leaky rectangular waveguide fluctuates with the tunnel size, and decreases with increasing of slot period, which are valuable for the design of the leaky rectangular waveguide used in Communications Based Train Control (CBTC) system.