Electromagnetic waves multi-path model based on image approach in tunnels

Multi-path propagation models of electromagnetic waves in tunnels are very important in resisting fading and enhancing communication quality. The differences between the wave-guide mode matching theory and ray tracing technology in predicting field were analyzed firstly in this paper, multi-path prediction model of the near-field environment in tunnels is established by using ray-tracing technique, and calculation means of total propagation distance and incidence angle and reflecting angle about three-dimensional helix ray based on image approach are presented. Finally propagation prediction model was simulated. The simulating results show that fading phenomena is very strong in tunnels, so propagation model is valuable of predicting field distributing.