The effect of the wall roughness on the electromagnetic wave propagation in coal mine underground

The effect of the wall roughness on the electromagnetic wave propagation in a rectangular tunnel of the coal mine underground is the concern of this paper. Also, the attenuation equation of the multi-mode propagation due to roughness is educed. The results of the simulations illustrate that the loss due to a typical wall roughness for mine tunnels increases with frequency. Because of the effect of the waveguides and the wall roughness in coal mine tunnels, there is a relatively good frequency group of the electromagnetic wave that propagates with low attenuation.