Electrostatic analysis of a comb-finger actuator with Schwarz-Christoffel conformal mapping

The design and the analysis of a comb-finger actuator require the evaluation of the coupling capacitances as well as the estimation of the electrostatic forces. Several approaches are possible: very rough approximations based on combinations of parallel plate capacitor elements, analytical or numerical Schwarz-Christoffel (SC) conformal mapping-based techniques, numerical solutions of the electrostatic field equations. Powerful numerical approaches can be very accurate, but heavy and time-consuming, while simple approaches are very inaccurate. A partially analytical approximate method based on SC conformal mapping is discussed. The comparison with results from standard simulators and experimental measurements demonstrates that the studied procedure is fast and satisfactorily accurate. (C) 2004 Elsevier B.V. All rights reserved.