Modeling in-plane misalignments in lateral combdrive transducers

The misalignment of lateral combdrive fingers was studied using analytical and finite element modeling techniques. Based on the principle of virtual work, the required driving force, and the forces and moments that develop during in-plane combdrive misalignment were analytically calculated. Electrostatic uncoupled 2D and 3D finite element models were then used to perform energy computations during misalignment. Finally, a stability analysis of misaligned combdrive fingers was performed using a coupled 2D finite element approach. The analytical and numerical results were compared and found to vary due to fringing in the electrostatic fields. The significance of the fringing fields and stability equilibrium states were subsequently discussed with respect to the design of precision MEMS devices.