An Application of the FD-TD Method for Analysis of MEMS Structures Using Body Fitted Grid Generation Method with Moving Boundaries

Abstract

Recently, MEMS technology is growing rapidly in RF field and the accurate design of RF MEMS devices require the computationally effective modeling of their transient and steady-state behaviors. In this paper, a numerical method to solve these MEMS devices using body fitted grid generation method with moving boundaries is proposed. This method is based on the finite-difference time-domain (FD-TD) method with an adaptive implementation of grid generation. The key feature of this method is time factor is added to the conventional numerical grid generation. Employing this transformation, it is possible to apply the grid generation technique to the analysis of geometries with time -changing boundary conditions. With such grid, the FD-TD method can be solved very easily using a time-invariant square grid regardless of the shape and the motion of the physical region. With this procedure, the numerical method for analysis of variable capacitor is shown. This technique can be easily generalized for the numerical simulation of RF MEMS structures that involve motion.