Temperature Independent Defect Monitoring Using Passive Wireless RFID Sensing System

A significant requirement of low-cost sensing systems for defect detection is essential to bridge the gap in non-destructive testing and evaluation and structural health monitoring. In practical situation, the temperature variation will be unknown ina prioriand hence will give rise to uncertainty and unreliability in the defect detection. This paper demonstrates the potential use of low-frequency radio frequency identification tag antenna-based wireless sensors to characterize corrosion and crack progression in high-temperature conditions for potential structural monitoring. Consideration of the parasitic parameters which depend on the temperature variation is presented. The key factors that influence the sensing accuracy with regards to different materials due to inhomogeneity are presented. A cost-effective self-compensation method is proposed by means of a self-swept frequency measurement through selection and fusion of temperature dependent feature near the tag’s resonance region. The experimental work validates the effectiveness of the method in temperature compensation and some initial results demonstrate the efficiency of the technique to overcome the inhomogeneity.