Comb drive resonator - QuickField simulation example
Engineering question
How to calculate electrostatic force and displacement in a MEMS comb resonator?
Answer
Calculate the electrostatic attraction force, transfer it to the coupled stress model, and solve for the comb displacement; symmetry allows only half of the geometry to be modeled.
Typical applications
MEMS comb resonators, microelectromechanical resonators, electrostatic microstructures
Download
- Download simulation files (files may be viewed using any QuickField Edition).
Simulation problem
Problem TypeAxisymmetric multiphysics problem of Electrostatics coupled to Stress analysis.
Geometry
Comb thickness Lz = 40 um.
Gap between fingers d = 2.5 um.
Given
Relative permittivity of air ε = 1,
Relative permittivity of dielectric ε = 10,
Potential difference ΔU = 40 V
Task
Find the attraction force and calculate displacement.
Solution
Geometry model features symmetry and only half of the comb was simulated.
Results
The attraction force is f = 2.4 uN.
Comb x-displacement is 7 nm.
Color map of electric field stress distribution and deformed shape of the comb (scaled 500 times).
Video
- Comb drive resonator