Langasite surface acoustic wave sensors: fabrication and testing

Area of Science:

• Materials Science
• Sensor Technology
• Physical Chemistry

Background:

• Harsh environments pose significant challenges for conventional sensor technologies.
• Surface Acoustic Wave (SAW) devices offer potential for robust sensing applications.
• Langasite (LGS) substrates are explored for their piezoelectric properties in high-temperature environments.

Purpose of the Study:

• To develop and demonstrate harsh-environment SAW sensors for both wired and wireless operation.
• To evaluate the performance of langasite-based SAW devices for temperature and oxygen sensing.
• To assess the feasibility of SAW sensors in extreme conditions up to 700°C.

Main Methods:

• Fabrication of SAW devices with interdigitated transducers and reflectors on langasite substrates.
• Implementation of radar-mode (pulse) detection for wired and wireless temperature sensing.
• Deposition of a Zinc Oxide (ZnO) layer for oxygen sensing capabilities.

Main Results:

• Achieved temperature resolution better than ±0.5°C between 200°C and 600°C.
• Successfully demonstrated oxygen sensing up to 700°C despite ZnO layer-induced attenuation.
• Validated both wired and wireless operation modes for temperature sensing.

Conclusions:

• Langasite SAW devices are a promising solution for harsh-environment temperature sensing.
• The developed SAW sensors show potential for reliable gas detection in extreme conditions.
• These findings support the use of langasite SAW technology in demanding industrial applications.