Measurement of the influence of antenna pattern on radio frequency propagation in a concrete tunnel

This paper investigates the influence of antenna pattern on radio frequency (RF) propagation in tunnel/mining environments. Propagation measurement results in a concrete tunnel using different antennas, i.e., omni-directional, Yagi, patch, and circular, are reported. Extensive measurements are carried out in various scenarios which include vertical, horizontal, and circular polarization for line-of-sight propagation (LoS) at four frequencies (455, 915, 2450, and 5800 MHz) that are common to many voice and data transport radio systems used in underground mines. The results show that antenna pattern has a strong influence on the uniformity of RF propagation gain in the near zone and does not significantly affect propagation behavior in the far zone except for a constant gain offset.