Gyroscopes of different types have a wide application in consumer electronics, industrial products, and medical devices. Recently, there has been increasing interests in military applications such as in the roll stabilization system and the inertial navigation system. The researchers carried out many studies to improve the sensor performance characteristics like sensitivity and stability. However, it still has some defaults.

To improve the sensor performance characteristics like sensitivity and stability, WANG Wen, HE Shitang, LI Shunzhou of Institute of Acoustics, Chinese Academy of Sciences, XU Fangqian of Zhejiang University of Media and Communications and Keekeun Lee of Division of Electronics Engineering, Ajou University conducted a series of studies and developed a new micro-rate sensor based on the shear horizontal surface acoustic wave (SH-SAW) gyroscopic effect.

The new SH-SAW propagating along the ST-90 degrees X quartz substrate with heavy metallization exhibits excellent temperature stability, large acoustic velocity, high electromechanical coupling factors, and very small propagation attenuation. The response mechanism of such an SH-SAW micro-rate sensor was established using partial-wave analysis methods. The angular detection sensitivity in the propagation path of SH-SAW was evaluated and the effect of the metal interdigital transducer (IDT) electrode thickness on the sensor performance was also studied, resulting in the realization of the optimized design parameters prior to fabrication. Two SH-SAW delay lines with a reverse direction and an operation of 80 MHz on the same chip are fabricated as the feedback of SAW oscillators. The single-phase unidirectional transducer (SPUDT) was used to structure the delay lines to decrease the insertion loss. The Coriolis force from the external rotation acts on the particles along the SAW propagation path, then a pseudo SAW was induced, and couples with the initial SH-SAW; thus, the SAW velocity was deviated. Meanwhile, the differential oscillation frequency was changed linearly and used to characterize the input angular rate. Then, using the precise rate table, the performance of the fabricated SH-SAW rate sensor was evaluated experimentally. A sensitivity of 1.268 Hz deg (-1) s (-1) at angular rates of up to 2000 deg s (-1), good linearity, and excellent temperature stability are observed.

This research result was published on the recently issued journal of JAPANESE JOURNAL Of APPLIED PHYSICS (49, 2010).