Modes of electromagnetic wave propagation in circular concrete tunnels

摘要

The modes of electromagnetic wave propagation in a circular tunnel with lossy walls such as concrete are obtained by applying the impedance boundary conditions on the wave solution inside the tunnel. The attenuation coefficients of the lowest order modes are calculated as a function of frequency. The results are found to agree well with the published results using other methods. An equation is proposed to represent the attenuation as a function of frequency and tunnel radius. This work can be easily extended to the case of rectangular tunnel.