The frequency characteristics of cyclic symmetry silicon gyroscope

The paper presents the frequency characteristics of silicon gyroscope with cyclic symmetry architecture. The conditions of existence about degenerate modes in cyclic symmetric structures were discussed, which broadens the potential structural designs. For the n=8 cyclic symmetric patterns, which are the most common applications, 2θ and 3θ modes are degenerate, and there is a non-degenerate solution for 4θ modes. Isotropic materials are also not necessary due to structural patterns also appear periodically. However, the crystalline cycle period is required to be consistent with the structural cycle period. The spectral responses at both the stiffness axis and non-stiffness axis were conducted. The layout adjustment reduces the frequency split from 70Hz to 20Hz with 0.05 degree spoke rotation, which is consistent well with the simulations. The electromechanical coupling model with electrostatic stiffness effect was used to simulate the frequency splits compensation. For the structure, 75 volts bias voltage is required for tuning 70 Hz frequency split.