UHF RFID-based low-power wireless sensor development for infrastructure health monitoring : issues in metallic environments

This paper investigates the critical issues of developing ultra-high frequency (UHF) radio frequency identification (RFID)-based low-power wireless sensors for infrastructure related metallic environments. Our studies show that the readability of tag antennas is considerably affected by the dimensions of the metallic mounts. Simulation results show that the surface current density distribution on the mount has a direct correlation with the measured readability. It is also shown that the wireless power flow towards the mounted tag antenna is significantly affected by the orientation of the metal mounts resulting in variable incident power. Furthermore, the studies show that the tag antennas de-tune considerably, due to the different shapes of the metal mounts. Both transmit and receive mode simulation results are in good agreement with the experimental measurements.