Coupled Nonlinear MEMS Resonators for Sensing

This paper describes the operation of weakly coupled resonators in the nonlinear domain in a closed loop configuration. The amplitude-frequency curves are mapped for both the resonators in the unstable regime to identify the two bifurcation points. The sensitivity of the amplitude ratio to input stiffness perturbations is experimentally determined for the two bifurcation points and compared to the sensitivity in a linear drive configuration. Similarly, the noise floor is measured at these operating points. It is observed that the input-referred noise floor is improved by approximately 2.5x by operating in the bottom-bifurcation point and by approximately 4x by operating at the top-bifurcation point in comparison to the linear drive configuration.