Enhanced sensitivity of a surface acoustic wave gyroscope using a progressive wave

Abstract

A surface acoustic wave (SAW)-based gyroscope with an 80 MHz central frequency was developed on two different piezoelectric substrates (128° YX LiNbO3 and ST-X quartz). A sensor was developed that contained two SAW oscillators. One oscillator was used as the sensing element and had metallic dots in the cavity between the input and output interdigital transducers (IDTs). The other oscillator was used as a reference element. Two oscillators were formed to extract the Coriolis effect by comparing the oscillation frequencies between these two delay lines, and metallic dots were used to induce a Coriolis force. Three different IDT structures were used to obtain a stable progressive SAW. Coupling of modes modeling was conducted prior to fabrication for determining the optimal device parameters. The device was fabricated and then measured on a rate table in accordance with the results of simulation. When the device was subjected to an angular rotation, the oscillation frequencies of the two oscillators were observed to differ. Depending on the angular velocity, the frequency difference was linearly modulated. The obtained sensitivity was approximately 62.57 Hz deg−1 s−1 at angular rates in the range 0–1000 deg s−1 in the case of the LiNbO3 substrate and single-phase unidirectional transducer and combed electrode structure. The dependence of the device performance on the piezoelectric substrate, IDT structure, and temperatures was also characterized. The developed device has good resistance to mechanical shock and stability to temperature.

Gyroscopes based on surface acoustic waves

“…Another type of SAW gyroscope using progressive waves was proposed by Oh et al [16,17]. Figure 9 shows the schematics and the mechanism of a SAW gyroscope based on a progressive wave which consists of a vibrating mass, an absorber, and a two-SAW delay line; one is used as a sensing element and contains a vibrating mass in a cavity, while the other is used as a reference element.…”

“…Moreover, Lee et al [15] and Wang et al [18] have attempted to improve the gyroscope sensitivity by using a differential scheme based on opposing wave propagation directions. Oh et al [16,17] constructed a SAW gyroscope using a progressive wave with different masses and positions for the metallic dot array on an experimental basis. In particular, Wang et al [18] successfully demonstrated a wireless and passive SAW gyroscope using two reflective delay lines.…”

Optimization of Surface Acoustic Wave-Based Rate Sensors

“…To achieve a breakthrough in the performance of the SAW-based rate sensor, a creative idea was proposed whereby a metallic dot array strategically deposited on the SAW propagation path of SAW devices was considered to enhance the Coriolos force acting on the propagating SAW [ 9 , 10 , 11 ]. The scheme of the proposed SAW rate sensor incorporating a metallic dot array is depicted in Figure 1 .…”

“…Obviously, the enhanced Coriolis force will improve significantly the detection sensitivity. Exciting detection sensitivity results (16.7 Hz·deg − 1 ·s − 1 ) were achieved with a 80 MHz rate sensor on X-112°Y LiTaO 3 with a 900 nm Cu dot array distribution [ 9 ]. This provides a good start to break through the detection sensitivity bottleneck of SAW-based rate sensors, even though there is still a great gap between the obtained sensitivity and the demands for real applications.…”

Localized laser vaporization of films with complex topologies for surface acoustic wave microgyroscope sensor

“…Перспективным направлением является использование микрогироскопов (МГ) на поверхностных акустических волнах (ПАВ), в основе которых лежит молекулярная кинетика твердого тела [3][4][5][6][7][8][9][10][11][12][13]. На сегодняшний день та-кие датчики активно разрабатываются как в России, так и за рубежом.…”