Enhanced Sensitivity of Surface Acoustic Wave-Based Rate Sensors Incorporating Metallic Dot Arrays

Abstract

Abstract:A new surface acoustic wave (SAW)-based rate sensor pattern incorporating metallic dot arrays was developed in this paper. Two parallel SAW delay lines with a reverse direction and an operation frequency of 80 MHz on a same X-112°Y LiTaO 3 wafer are fabricated as the feedback of two SAW oscillators, and mixed oscillation frequency was used to characterize the external rotation. To enhance the Coriolis force effect acting on the SAW propagation, a copper (Cu) dot array was deposited along the SAW propagation path of the SAW devices. The approach of partial-wave analysis in layered media was referred to analyze the response mechanisms of the SAW based rate sensor, resulting in determination of the optimal design parameters. To improve the frequency stability of the oscillator, the single phase unidirectional transducers (SPUDTs) and combed transducer were used to form the SAW device to minimize the insertion loss and accomplish the single mode selection, respectively. Excellent long-term (measured in hours) frequency stability of 0.1 ppm/h was obtained. Using the rate table with high precision, the performance of the developed SAW rate sensor was evaluated experimentally; satisfactory detection sensitivity (16.7 Hz•deg•s ) and good linearity were observed.

Surface Acoustic Wave Gyroscopic Effect in an Interdigital Transducer

“…Figure 4a displays the results obtained by FEM, while Figure 4b depicts the results obtained via partial-wave analysis. The analysis of the results were discussed by Wang et al [1,12]. We want to elaborate upon the parameters a , b , and v 0 .…”

“…The partial-wave analysis method [1,22] was used to consider the SAW gyroscope effect in a structure composed of a semi-infinite piezoelectric substrate and an Au layer over the substrate. The structure is shown in Figure 1.…”

“…Surface acoustic wave (SAW) gyroscopes have received increasing attraction because of their many unique properties including inherent shock robustness, small size, low cost, and long working life [1]. SAW gyroscopes can be used to measure angular rates through a rotation-induced secondary SAW or rotation-induced frequency shifts in SAW on the surface of the piezoelectric material.…”

“…The results showed that the velocity varies in the Rayleigh wave and the Bleustein–Gulyaev (BG) wave with the ratio of angular rate to the frequency. Some numerical results for 128°YX-cut LiNbO 3 and X-112°Y LiTaO 3 were presented [1,12] to illustrate the effects of the Coriolis force and the centrifugal force on the Rayleigh wave. Sizov et al proposed an analytical solution to the problem of elastic waves propagation in a structure comprising a carrying foundation upon which a piezoelectric layer was applied and was being subjected to constant rotation [13].…”

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 .…”