Pulse-mode temperature sensing with langasite SAW devices

Wired and wireless surface acoustic wave (SAW) sensors with langasite Euler angle (0, 138.5, 27) and (0, 138.5, 117) were fabricated for the purpose of temperature and gas sensing in high temperature combustion process. Their temperature responses were measured in pulse mode both wired to a high-temperature cable and in wireless mode attached to a dipole antenna. The observed surface acoustic wave velocity monotonically decreases above 200°C with multiple reflections observable in wired measurements up to 900°C and in wireless mode up to 700°C. Temperature resolution better than ± 0.5°C was achieved for wired and wireless measurements from 200°C to 600°C.