A New Design of Mode-Matched (100) Silicon Ring Gyroscope with Chamfered Rectangle Springs Immune to Fabrication Error

In this report, we proposed a new design of mode-matched (100) single crystal silicon (SCS) ring gyroscope immune to fabrication errors. The robustness against dimensional and orientation errors was confirmed by finite element analysis simulations and frequency response measurements. The designed ring resonator has a ring of uniform width suspended by eight identical suspension structures and it has eight-fold symmetry. The in-plane elastic asymmetry of the ring is compensated by the carefully designed suspension structures with four rectangular beams with two chamfered corners in each. As a simulation result, we found that the optimum chamfering size for the ring width of 5.1 $\upmu\mathrm{m}$ and the diameter of 2 mm and the ring resonator is almost insensitive to fabrication errors. The resonators were fabricated using silicon-on-insulator wafers and the as-fabricated device shows small mismatch about 0.5 - 1.5%, which is caused by the nonuniform fabrication errors. After electrostatic tuning, gyro output was successfully measured.