Flexible instrumentation for wireless SAW

Wireless surface acoustic wave sensors are attractive in harsh environment applications, for example for temperature and gas sensing in combustion system exhausts. Pulse- mode sensing separates the stimulus and response signals temporally, increasing the allowable separation between antennas. Previous researchers have typically used custom electronics for extraction of the phase shift between two reflections. We describe a flexible laboratory system for accurate measurements of the phase shift, and demonstrate its application. We report on wired and wireless temperature measurements up to 900 and 700°C, respectively using langasite surface acoustic wave devices.