The Equivalence of the Ray Tracing and Modal Methods for Modeling Radio Propagation in Lossy Rectangular Tunnels

Ray tracing and modal methods are widely used for modeling RF propagation in tunnels. In this letter, we show that the two methods are mathematically equivalent and yield the same results. We also compare the theoretical predictions from both methods to field measurements at different frequencies (455, 915, 2450, and 5800 MHz) and find good agreement.