Electromagnetic wave propagation in two‐dimensional impedance tunnels with modified multicross‐junctions

As a model for the electromagnetic wave propagation in a tunnel-shaped structure with branches and bends such as an underground shopping center and a street lined with buildings, a two-dimensional tunnel with modified multicross junctions is studied both theoretically and experimentally for wave propagation. The basis of the theoretical analysis is to neglect the higher-order multiple scattering effect and to consider the field as the cascaded connection of the results of the modified single-cross junction. As the boundary condition of the tunnel wall, the surface impedance approximation is employed. The present results can be applied to special tunnels made of cascaded connection of the modified cross, step and T. In the experiment, a microwave simulation is carried out for a tunnel model made of concrete. It is found that the numerical results of the electric field intensity in the tunnel agree well with the experimental results.