UHF RFID tag IC power mode switching for wireless sensing of resistive and electrochemical transduction modalities

We propose the concept of using the change in the state of an RFID tag IC from passive to battery-assisted passive (BAP) as an indicator for sensing. We demonstrate how this approach is particularly well suited for transduction mechanisms that produce charge, such as electrochemical reactions through a case example in glucose sensing. We demonstrate that our sensor is capable of detecting glucose at different concentrations from 5-30% by measuring the amount of time the tag IC stays in BAP mode. We also demonstrate through a simulated experiment how our approach is capable of sensing resistivity changes associated with low concentration changes in gas sensing applications. The advantages and limitations of our approach relative to the state of the art tag-based sensors and future directions of research are also discussed.