A novel shock and heat tolerant gyrosensor utilizing a one-port surface acoustic wave reflective delay line

作者:Oh Haekwan*; Fu Chen; Yang Sang Sik; Wang Wen; Lee Keekeun
来源:Journal of Micromechanics and Microengineering, 2012, 22(4): 045007.
DOI:10.1088/0960-1317/22/4/045007

摘要

A surface acoustic wave (SAW)-based gyroscope with an 80 MHz central frequency was fabricated on a 128 degrees YX LiNbO3 piezoelectric substrate. The fabricated gyroscope is composed of a SAW resonator, metallic dots and a SAW reflective delay line. The SAW resonator, which is activated by a voltage-controlled oscillator, generates a stable standing wave with a large amplitude at an 80 MHz resonant frequency, and the metallic dots induce a Coriolis force and generate a secondary SAW in the direction orthogonal to the propagating standing wave. The SAW reflective delay line is employed to measure the Coriolis effect by analyzing the deviations in the resonant frequency of the SAW reflective delay line. A combined finite element method/boundary element method was utilized to extract the optimal device parameters prior to fabrication. The device was fabricated according to the modeling results and then measured on a rate table. When the device was subjected to an angular rotation, a secondary SAW from the vibrating metallic dots was generated owing to the Coriolis force, resulting in a perturbation of the propagating SAW in the SAW reflective delay line. Depending on the angular velocity, the reflection peak of SAW reflective delay line was changed linearly, and this change was measured by the network analyzer. The measured results matched the modeling results well. The obtained sensitivity was approximately 1.23 deg/(deg/s) in an angular rate range of 0-2000 deg s(-1). Good thermal and shock stabilities were observed during the evaluation process proving the shock and heat robustness of the fabricated SAW gyroscope.