Mode-Matched Bulk Acoustic Wave Disk Gyroscope Utilizing Pseudo-Extensional Mode

In this paper, a mode-matched BAW (bulk acoustic wave) gyroscope operating in the pseudo-extensional mode is firstly proposed utilizing a resonator structure as a combination of a ring and a disk resonator. The pseudo-extended mode is realized by coupling the orthogonal wineglass modes of ring and disk resonators in the anti-phase motion, i.e. the adjacent ring and disk alternatively expand and contract. The anisoelasticity of single crystal silicon (SCS) can be compensated by optimizing the coupling strength between ring and disk resonators, showing the minimum frequency mismatch as small as 13 ppm. The proposed resonator is decoupled from the substrate by a folded beam design with a low anchor loss as a result of a high Q
Anchor
8.7×10
⁷
. Compared with the n=3 wineglass mode, the proposed design operated in the pseudo-extended mode has a higher resonant frequency as 1.34 MHz and an angular gain as 0.52.