A concentrated springs architecture for single-digit frequency symmetry in Si MEMS gyroscope

We report on a new design approach for X-Y symmetric resonator, that can be mechanized as rate (RG) or rate-integrating gyroscope (RIG), with a single digit as-fabricated frequency split between the two mechanical out-of-phase operational modes. We explore concentration of critical mechanical elements (shuttle-spring-anchor modules) close to the center of the die to mitigate the effect of the fabrication tolerances “intra-device”. Characterization results show sub-Hz as-fabricated frequency split of Δf=0.3Hz, the lowest value found in the literature for silicon MEMS gyroscopes. Preliminary ring down test shows Q factor greater than 330K. Both low Δf and high Q factor obtained in this approach makes it a very good candidate for implementation of high performance gyroscope.