The 3D Capacitance Modeling of Non-parallel Plates Based on Conformal Mapping

A highly accurate three-dimensional (3D) capacitance analytical model of parallel plates is important for the optimal design of electrostatic MEMS devices. However, due to constraints of fabrication processes, two parallel conducting plates are ineluctably tilted at an angle. Basically, finite element analysis (FEA) seems the preferred access to evaluate fringing effects across the non-parallel plates, while the analytical solution is not available. In this work, we present an analytical model for the 3D capacitance of a non-parallel-plate structure using the conformal mapping method. Taking the fringing effect into account, the proposed model shows a high accuracy of 95%, compared with other models.