Wireless Surface Acoustic Wave Radio Frequency Identification (SAW-RFID) Sensor System for Temperature and Strain Measurements

The testing, validation, and monitoring of aero-structural design and health conditions require a non-intrusive and in-situ means to provide real time strain/stress and vibration data of turbine engine structures. However, taking such a measurement is difficult due to the extremely harsh environment in turbine engines. The SAW-RFID sensor provides a promising tool to operate in such a harsh environment, because it takes advantage of being passive, wireless and tolerant for high temperatures. These characteristics give it the ability to measure the strain/stress and temperature on engine blades in real time. In this paper, we present our work on the design, fabrication and testing of SAW-RFID devices as wireless temperature and strain sensors. The SAW-RFID sensors were first designed based upon the Finite Element Modeling (FEM). These sensors are then fabricated with micro-fabrication techniques. The antennas of the SAW sensor and RFID reader were also developed. The fabricated sensors were tested. Finally, we demonstrate the capability of our SAW sensor for the temperature and strain measurements, which show the consistence with the simulation values.