Feedthrough parasitic nonlinear resonance in micromechanical oscillators

Abstract

Mechanical oscillators incorporating miniaturized structures to transduce mesoscopic motion as readable electrical signals are often limited by the feedthrough effect (FE) because oscillation features are corrupted. The knowledge of FE parasitic resonance hitherto is only demonstrated in the linear regime. Herein, we reveal the nature of phenomenological FE parasitic nonlinear resonance. An inverse distortion in the spectra resulting from the superposition of Duffing nonlinearity and the FE is observed and modeled with physical insight into the governing parameters. We find that the manipulation of electromechanical coupling of the oscillator can fully de-embed the FE, while the device oscillates at the nonlinear bifurcation point under phase control. The generic nature of our model indicates that similar dynamic behaviors will occur for the nonlinear resonant systems containing the FE, regardless of transducing techniques. The strategy of on-chip FE control in our capacitive platform is scalable and can be suitably transformed for application in oscillators employing alternative transducers.