Optimization of a Cantilever Microswitch with Piezoelectric Actuation

ABSTRACT: This paper considers MEMS microswitches with piezoelectric-film actuation. A mathematical actuator model is established that accounts for normal stress at the piezo– substrate interface, in addition to shear stress. This model gives more accurate predictions for relatively thicker piezoelectric layers. Maintaining adequate contact force between switch electrodes is important in ohmic-contact switches, but parallel contact geometry is also important in switches that provide capacitive coupling between the signal lines. Furthermore, ‘off-state ’ isolation is governed by electrode gap when open. The presented mathematical model demonstrates the relationships between these factors and the switch geometry. Optimum conditions are derived. Key Words: MEMS microswitches, piezoelectric actuation, optimizatio