Characteristics of Electromagnetic Guided Waves for Communication in Coal Mine Tunnels

We obtain numerical results of the attenuation and phase constants of the lowest order modes in a rectangular tunnel with an axial wire for various values of physical parameters that are important in intramine communications and remote control. Besides the perturbed free modes of the empty guide, a TEM-like mode, which is highly influenced by the wire impedance and location, is identified. Also the excitation mechanisms of the modes are considered from the standpoint of point-to-point communication within a mine tunnel.