Mechanical Vibration Characteristics for the Driving Part in Array of Microelectromechanical Systems Vibratory Gyroscopes

• Published in: Japanese Journal of Applied Physics 2012-09, Vol.51 (9), p.097201-097201-8
• Main Authors: Miyake, Yoshinori, Hirata, Masaki, Suzuki, Kenichiro
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.51.097201

Over the past ten years, much effort to develop microelectromechanical system (MEMS) gyroscopes with the "tactical" and "inertial" grade has been made. Although several techniques are proposed to increase the sensitivity, each of them has serious tradeoffs with other characteristics. We propose a new approach to accomplish the increase in sensitivity. The overall gyroscope consists of gyroscope elements arrayed in an $X$--$Y$ matrix. Each gyroscope element is connected with two types of beams, coupling and connecting beams, and is excited in the antiphase vibration mode. First, this array configuration takes the advantage of the large scale factor of $N^{2}$, the square of the number of elements, for the sensitivity over a simply large chip (the sensitivity is proportional to $N$). Second, the vibrational characteristics are not changed from those for a single element irrespective of the number of elements. Therefore, much effort in design can be saved. $1\times 2$ and $2\times 2$ arrays with the resonant frequency of approximately 5 kHz were fabricated and evaluated in terms of the resonant frequency and amplitude for each element. They agreed well with those of a single gyroscope. This indicates that the proposed array helps to reduce the task of frequency tuning, which is needed for conventional $1\times 2$ gyroscope arrays. It is also useful to fabricate a highly resonant gyroscope, which is immune to environmental noise.