Authors: F. Li, J.V. Clark
Affilation: Purdue University, United States
Pages: 597 - 600
Keywords: comb drive, levitation, Schwarz-Christoffel mapping, online tool
Lumped comb drive models found in the literature ignore the electrostatic levitation effect, which decreases their accuracy. The levitation effect occurs when the substrate is within close proximity to the comb drive. This common configuration causes the comb drive to deflect away from the substrate upon actuation. Previously, modeling the levitation effect on a large number of comb drive fingers was limited to lengthy computer simulations using finite element analysis (FEA). In this paper, we show that the electrostatic forces causing the levitation effect can be computed much more quickly and precisely by using Schwarz-Christoffel mapping (SCM). Compared to FEA, our speed improvement is because the SCM solver does not discretize the boundaries and subdomains into a large number of coupled equations, and our precision improvement is due to SCM’s ability to treat electrostatic forces at vertices exactly, unlike FEA. We have developed an easy-to-use tool based on our algorithm, available at NanoHUB.org. We use a public SCM toolbox to find the electric potential field, from which the electrostatic levitation force can be found. Our result is 1.6% larger than the conventional one.