Low cost thin film based surface acoustic wave vibration sensors for vibrational gyroscope

Reports on the development of thin film polycrystalline zinc oxide based surface acoustic wave (SAW) resonators for use as vibration sensors on a novel low cost vibrating gyroscope structure intended for use in a GPS-INS automotive navigation system. Piezoelectric growth conditions and layer configurations are optimised to produce resonators with the high Q factor (>4000) required to detect kHz frequency strains in a macroscopic (3cm diameter) vibrating structure. The system is ultimately intended to use contact free capacitive coupling schemes to the sensors for primary and secondary mode detection. Initial strain sensitivity measurements of the SAW resonators have been performed, revealing a practical strain sensitivity of approximately 0.7845 kHz//spl mu/strain.