Universal pressure and temperature SAW sensor for wireless applications

This work presents a universal SAW sensor device for measurement of either pressure or temperature or both simultaneously. An arrangement of three surface acoustic wave resonators (SAWRs) was used. The experimental sensor described in this paper employs a 35/spl deg/ Y cut quartz diaphragm and utilizes center frequencies ranging from 433 to 436 MHz. The sensor relies on differences in the dependence of each SAWR center frequency on pressure and temperature. A difference frequency measurement was used. The difference frequency outputs were used to determine pressure and temperature.