Modeling of radiowave propagation in tunnels

We investigated propagation of radio frequency (RF) waves in tunnels. An understanding of RF propagation in tunnels is needed to plan for optimal radio communication system performance. We considered tunnels with a square cross section and right-angle junctions. We developed an analytic model of tunnel propagation by considering multiple reflections from tunnel walls and diffraction around junction corners. A comparison of model results with measurements shows a strong correlation between model predictions and measured data. Finally, we briefly describe a software tool that helps users visualize field strength of the propagating field in tunnels.