Characterization of langasite as a material for SAW based RFID and sensing systems at high temperatures

For langasite, a piezocrystal used as substrate material for SAW-based ID tags and sensors operating at high temperatures, the parameters of SAW propagation have been determined as a function of temperature. These parameters are the phase velocity, propagation loss, and electromechanical coupling coefficient. Two crystal cuts have been studied, with Euler angles (0deg, 138.5deg, 26.6deg) and (0deg, 30.2deg, 26.6deg). The SAW parameters were obtained from the measurements of transfer functions for delay lines on langasite chips at frequencies ranging from 150 MHz to 1 GHz and at temperatures from room temperature up to 750degC.