Propagation in circular tunnels: ring source excitation

We present a model for propagation in lossy circular tunnels. Our study has potential application to wireless communication in highway and railroad tunnels where the cross-sectional geometry is often circular except for the roadbed. In addition, the circular tunnel model has relevance to wireless communication in underground nuclear waste storage facilities, such as that planned for Yucca Mountain, Nevada, USA. Our principal goals are: (1) to provide insight into strategies for the placing of transmitting antennas and receiving sensors at various positions in a tunnel; and, (2) to provide criteria for antenna design.