A Full-System Dynamic Model for Complex MEMS Structures
L.A. Rocha, E. Cretu and R.F. Wollfenbuttel
Delft University of Technology, NL
Keywords: MEMS modeling, squeeze film damping, large-signal analysis, macro model
For full characterization of a surface micromachined MEMS device, where the thickness of the moving layer is just a few times the gap size, the modeling has to take large-signal behavior and end effects into account. In this work, a numerical method using finite differences is implemented in Simulink to solve the Reynolds equation. The spatial derivatives are solved using the finite differences. The use of the Simulink capabilities for time integration allows solving of the time derivatives at any mesh point. To increase efficiency, a low-level language is used inside Simulink to solve the parameterized finite differences and the time derivatives. As the Reynolds equation is being solved inside a high-level language description, other system parameters (such as: mass, spring constant, non-trivial geometry) can be easily incorporated. Measurements on a complex 2DOF MEMS device are compared with simulation results, and the agreement validates the full system approach proposed.
Nanotech 2004 Conference Technical Program Abstract