A numerical method to derive accurate temperature coefficients of material constants from high-temperature SAW measurements: application to langasite

Pascal Nicolay (1) , Thierry Aubert (2)

1 CTR - Carinthian Tech Research
2 SYMME - Laboratoire SYstèmes et Matériaux pour la MEcatronique

The design of wireless SAW sensors for high-temperature applications requires accurate knowledge of the constitutive materials' physical properties in the desired temperature range. In particular, it is crucial to use reliable temperature coefficients of the stiffness, piezoelectric, dielectric, and expansion constants of the propagation medium to achieve correct simulations of the considered devices. Currently, the best-suited piezoelectric material for high-temperature SAW applications is langasite (LGS). Unfortunately, the available coefficients do not allow for precise prediction of the temperature dependence of LGS-based SAW devices above 300°C. A novel method, based on a simulated annealing algorithm cou- pled with a Rayleigh wave simulation program, was developed to find optimal LGS temperature coefficients. This approach has proven to yield accurate results up to at least 800°C.

Domaines: Physique [physics]

Pascal Nicolay, Thierry Aubert. A numerical method to derive accurate temperature coefficients of material constants from high-temperature SAW measurements: application to langasite. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2013, 60 (10), pp.2137-2141. ⟨10.1109/TUFFc.2013.2804⟩. ⟨hal-00923011⟩