Radio Wave Attenuation Character in the Confined Environments of Rectangular Mine Tunnel

The radio waves are more complex in confined environments such as coal mine tunnels, in order to obtain the propagation character of radio wave in the confined environments of mine tunnel, the electric-field intensity and magnetic-field intensity of horizontal polarization wave are obtained according to Maxwell equation and boundary condition of tunnel. The attenuation coefficients of electric field in horizontal and vertical polarization are deduced through the traveling wave condition of confined space. The attenuation characters of different position transmitter in rectangular mine tunnels are simulated in an experiment tunnel. The results shows the attenuation of electric-field intensity is increase quickly in 50m.When the transmitter is more close to the wall of the mine tunnel, the mode of propagation is more complex and the attenuation is more serious, whereas in the middle of the mine tunnel, the attenuation rate of radio is the least. Factors that influence the attenuation character of radio waves in mine tunnel are analysed and simulated too, it is benefit to evaluate the wireless channel quality in mine tunnel.