Optimal Antenna Installation Position Analysis for Wireless Networks in Underground Tunnels

Field coverage is strongly affected by the antenna position because of the multimode waveguide characteristics in the underground tunnel. This is critical for the wireless system to have a satisfied performance. In order to investigate the optimal installation location of the antenna in tunnel, the coupling relation between the antenna current distribution and the propagation modes in the underground tunnel is derived. On this basis, the best excited modes, the coupling loss and the radio coverage for antenna at different positions are compared and discussed. Results show that the most suitable installation location for the non-mobile wireless nodes such as AP is the middle of the tunnel ceiling.