Modeling, Analysis, and Experimental Validation of a Bifurcation-Based Microsensor

The potential to detect very small amounts of added mass has driven research in chemical and biological sensors based on resonant micro- and nanoelectromechanical systems over the past two decades. While traditional resonant mass sensors utilize chemomechanically induced shifts in linear natural frequency for mass detection, alternate sensing approaches which exploit near-resonant nonlinear behaviors have garnered interest from the research community due to their potential to yield improved sensor metrics and to simplify final device implementations. This paper investigates the development of an amplitude-based mass sensing approach which utilizes the dynamic transitions that occur near a cyclic-fold/saddle-node bifurcation in the nonlinear frequency response of a piezoelectrically actuated microcantilever. Specifically, the work details the modeling, analysis, and experimental validation of this mass sensing technique. The experimental results presented here not only prove the feasibility of the proposed sensing approach but also allow for the direct evaluation of pertinent sensor metrics.