Design-dependent performance of self-actuated and self-sensing piezoelectric-AlN cantilevers in liquid media oscillating in the fundamental in-plane bending mode

In this work the electrical performance of micromachined piezoelectric cantilevers having different designs is investigated in liquid environment, thus making most beneficially use of their self-actuated and self-sensing capability. The impact of parasitic effects originating from e.g. the electrical feedlines, on the sensing characteristics is discussed. The focus is set on in-plane bending modes excited in a large viscosity range from 1.09 cP to 238.82 cP and the corresponding influence on the conductance peak, which is important especially for liquid monitoring purposes. Furthermore, an analytical model for the dynamic admittance and the conductance peak is presented and compared to the measurements. Based on these results design guidelines for optimizing the performance of piezoelectric in-plane resonators are presented.