Low frequency (LF) RFID sensors and selective transient feature extraction for corrosion characterisation

• Passive LF RFID sensing system for corrosion detection on mild steel samples with corrosion exposure between 1 & 12 months.
• Different feature extraction and selection of features for corrosion characterisation.
• Sensitivity enhancement of RFID response using ferrite core for further corrosion characterisation.

In this paper, Low Frequency (LF) RFID sensing system is used to characterise marine atmospheric corrosion on steel samples. Considering the conductivity and permeability variation in the corrosion layer, optimisation of sensing sensitivity and communication distance of commercial RFID tags placed on both coated and uncoated samples (exposure duration between 1 and 12 months) for impedance matching and appropriate operation frequencies are analysed. To balance the communication distance between RFID reader and tag and to match the impedance variation of RFID tags on metallic samples, a concept of wireless power transfer (WPT) through strongly coupled magnetic resonance (SCMR) method at RFID is applied. Static and transient features are extracted and selected to characterise corrosion. To enhance the sensing sensitivity to corrosion characterisation, further experimental studies have been carried out using ferrite sheets. The proposed LF RFID sensing system has been validated using commercial RFID tags with different feature extractions and selection of features for corrosion characterisation.