An alternatively efficient method (DBEM) for simulating the electrostatic field and levitating force of a MEMS combdrive

Abstract

For MEMS combdrive design, the reduction of levitating force due to electrostatic fields is very important, and an accurate electrostatic analysis is essential and indispensable. For diverse MEMS combdrive designs, the boundary element method (BEM) has become a better method than the domain-type finite element method (FEM) because the BEM can provide a complete solution in terms of boundary values only, with substantial saving in modeling effort. Since dual BEM (DBEM) has some advantages over conventional BEM for a singularity, the DBEM was used to simulate the fringing of field around the edges of the fixed fingers and movable fingers of MEMS combdrives for diverse design cases. A number of electrostatic problems for typical MEMS combdrive designs were analyzed to check the efficiency and validity of this new technique. It is found that the numerical results computed by coarse mesh DBEM match the reference data from a large refined mesh FEM very well, and the accuracy and performance of DBEM are also better than those of conventional BEM for solving the electric intensity field of MEMS combdrives. By way of the DBEM presented in this paper, an accurate and reasonable electrostatic field can be obtained, and the follow-up control method of levitating force for the MEMS combdrive can be implemented more precisely.