Squeeze-film Damping Effect Research Articles

Physically based modeling of squeeze film damping by mixed-level system simulation

We propose a mixed-level simulation scheme for squeeze film damping (SQFD) effects in microdevices, which enables the inclusion of these effects in system-level models of entire microsystems. Our treatment of SQFD follows a natural physically based and flexible methodology, which also allows for complex geometries and coupling between different energy and signal domains. The proposed damping model is realized in VHDL-AMS and, therefore, can easily be included in system-level models for full system simulation. Results obtained for elementary and complex microstructures show excellent agreement with 3D Navier–Stokes-based FEM simulations, but are computationally by far less expensive, thus proving the quality and power of our approach.

Mechanical design and optimization of capacitive micromachined switch

Design and optimization of a shunt capacitive micromachined switch is presented. The micromachined switch consists of a thin metal membrane called the “bridge” suspended over a center conductor, and fixed at both ends to the ground conductors of a coplanar waveguide (CPW) line. A static electromechanical model considering the residual stress effects is developed to predict the effective stiffness constant and the critical collapse voltage of the bridge for several typical bridge geometries. The deformation of the bridge and its contact behavior with the dielectric layer are analyzed using the finite element method (FEM) in order to explore a good contact field with different bridge geometries. Furthermore, a nonlinear dynamic model that captures the effects of electrostatic forces, elastic deformation, residual stress, inertia, and squeeze film damping is developed, and is used for predicting the switching speed (including the switching-down and the switching-up time) and the Q-factor. The effects of variation of important parameters on the mechanical performance have been studied in detail, and the results are expected to be useful in the design of optimum shunt capacitive micromachined switch. The results may also be useful in the design of actuators with membranes or bridges.