Electromagnetic Mode Theory of Periodically-Loaded Oversized Imperfect Waveguide and Its Application to the Propagation of Radio Waves in Long Wall Coal Mining Face Tunnels

A long wall coal mining face tunnel is idealized as a periodically-loaded oversized imperfect rectangular waveguide. A rigorous solution for the electromagnetic field distribution is presented. The theoretical analysis is mainly concentrated on obtaining the characteristic equations for HEM and TE modes and reductions are carried out to obtain the mode equations in a form suitable for the numerical computation. The propagation constant of the TE
_m0
mode is computed. The calculated and measured propagation attenuation rates of the dominant TE
₁₀
mode are compared for a scaled model. They are in good agreement, showing the validity of the theory.