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

Microelectromechanical chemical and biological sensors have garnered significant interest over the past two decades due to their ability to selectively detect very small amounts of added mass. Today, most resonant mass sensors utilize chemomechanically-induced shifts in the linear natural frequency for detection. In this paper, an alternative, amplitude-based sensing approach, which exploits dynamic transitions across saddle-node bifurcations that exist in a microresonator’s nonlinear frequency response, is investigated. In comparison to their more traditional, linear counterparts, these bifurcation-based sensors have the ability to provide improved sensor metrics, eliminate power-consuming hardware from final sensor implementations, and operate effectively at smaller (e.g. nano) scales. The present work details the ongoing development of a bifurcation-based mass sensor founded upon the near-resonant response of piezoelectrically-actuated microcantilevers. Specifically, the work details the modeling and analysis of these devices, their functionalization, and proof-of-concept mass sensing experiments which not only validate the proposed technique, but allow for the direct evaluation of pertinent sensor metrics.