A novel radiator for a 2.4 GHz wireless unit to monitor rail stress and strain from a train mounted receiver

In this paper, we present an antenna design which can be integrated near the rail and which is sufficiently rugged to withstand weather conditions and rail stresses without appreciable changes in its operational mode. The proposed concept is based on fabricating a metal package mounted to the side of the rail. This metal block serves the purpose of housing the transceiver as well as the antenna. The latter was based on a cavity resonator properly excited to generate the desirable pattern and gain characteristics. The cavity location and geometry presented a challenge and several configurations were considered. As part of the final design, effects on the pattern coverage due to rail presence were also considered. Below we discuss the system requirements, antenna design, and hardware evaluation of the entire sensor system.