Platinum/AlN/Sapphire SAW resonator operating in GHz range for high temperature wireless SAW sensor

In this work, Pt/AlN/Sapphire SAW resonator operating in 2.45GHz ISM band is studied as a potential sensor for high temperature and high frequency applications. Experimental characterization was realized using a specific station probe between room temperature and 500°C. Results show that electromechanical factor of the structure (K²) increase with temperature, while the quality factor decreases. The variation of frequency with temperature shows a good linearity, which is very useful for temperature sensor applications and the measured TCF of -35 ppm/°C is consisting with modeling predictions.