Langasite Based Surface Acoustic Wave Sensors for High Temperature Chemical Detection in Harsh Environment

Abstract This work presents a stand-alone portable device for high temperature assessment. The system includes a Langasite (LGS) acoustic sensor, a ceramic heater and a platform with RF connections for remote in-situ measurements. The packaging consists in a hermetic stainless steel cell which enables safe gas detection. In situ temperature measurements have been achieved thanks to the integrated heater and have been compared with finite element modeling. The thermal behavior was successfully investigated in the temperature range 25-450°C. The resulting experimental data have been compared with different theoretical models, using several sets of LGS constants, and their agreement is discussed.

[1]  K. Yamaguchi,et al.  Experimental and theoretical analysis of SAW properties of the langasite substrate with Euler angle (0/spl deg/,140/spl deg/,/spl phi/) , 1999, 1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027).

[2]  M. Pereira da Cunha,et al.  High temperature LGS SAW gas sensor , 2006 .

[3]  Y. Pisarevsky,et al.  New data on temperature stability and acoustical losses of langasite crystals , 1995, Proceedings of the 1995 IEEE International Frequency Control Symposium (49th Annual Symposium).

[4]  M. D. da Cunha,et al.  Recent measurements of material constants versus temperature for langatate, langanite and langasite , 2000, Proceedings of the 2000 IEEE/EIA International Frequency Control Symposium and Exhibition (Cat. No.00CH37052).

[5]  Holger Fritze,et al.  Langasite for high-temperature acoustic wave gas sensors , 2003 .