Finite element modeling of electrostatic MEMS including the impact of fringing field effects on forces

The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking fringing fields into account is crucial for an accurate computation of the electrostatic forces. In this work, the finite element method is applied for modeling electrostatic actuators. The electrostatic force distribution is obtained by locally applying the virtual work method. A micro-beam and a comb drive are considered as test cases. The impact of the fringing field effects on the accurate computation of electrostatic forces and capacitances is shown through 2D and 3D parametric studies.