Transition Point of the Radio Wave Propagation Generated by Antennas in Rectangular Tunnels

Radio wave propagation characteristics generated by antennas in rectangular tunnels are studied in this paper. A hybrid propagation model is used to describe the propagation characteristics, and the property of the transition points between different propagation models (regions) are analyzed by the waveguide modal method. The results indicate that the location of the transition point is significantly related to the beam width and beam direction of the transmitting antenna and the tunnel dimension. The results are valuable for layout design of the antenna system of wireless communication in confined space.