Electrostatic Comb Drive Design

Abstract—Microelectromechanical Systems (MEMS) has led to a drastic development in the field of sensors. This paper presents a new design of a electrostatic comb drive with different parameters. The analysis of MEMS electrostatic comb drive is done with different structures. An increased displacement of lateral comb drive actuator will subsequently be accomplished with the same actuation voltage. COMSOL Multyphysics 4.4 is used for designing the comb drive. It offers Finite element analysis to prove the concept of displacement of movable comb fingers, achieved by the amount of electrostatic force generated by the device.
Keywords—MEMS; Electrostatic comb drive; Finite element analysis; Electrostatic force.
I. INTRODUCTION
MEMS is a technology

Comb drive with Crab leg flexure spring: An electrostatic comb drive with crab leg flexure beam is shown below.
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Fig.3.Electrostatic comb drive with crab leg flexure beam.
In the above figure all the parameters are same as comb drive with fixed-fixed spring but only at the end of the spring, a crab leg like structure is added with a height of 30 μm.
B. Comb drive with double folded flexure spring: An electrostatic comb drive with double folded flexure spring is shown below.
Fig.4.Electrostatic comb drive with double folded flexure beam.
In the above figure a folded flexure beam is introduced with the same beam length i.e 280 μm.
C. Comparison: The figure below shows the displacement of all the comb drives when the same potential is applied .
Fig.5. Displacement Vs Voltage graph in comb drive with fixed-fixed flexure beam
Fig.6. Displacement Vs Voltage graph in comb drive with Crab leg flexure beam
Fig.7. Displacement Vs Voltage graph in comb drive with double folded flexure beam
The capacitance is a function of displacement. So with change in displacement, capacitance changes [4]. Therefore the change in capacitance with potential is shown