Doubling flexural frequency response using synchronised oscillation in a micromechanically coupled oscillator system

A simplified oscillation system, which consists of two beam-shaped cantilevers, was designed, fabricated and characterised for demonstrating synchronised oscillations and considering the eigenstate (frequency) amplification mechanism for possible sensing applications. Two geometrically different cantilevers, with resonant frequencies of 351.66kHz (ω₂ for detecting) and 177.38kHz (ω₁ for sensing), are coupled by one coupling overhang. Under synchronised oscillation, the frequency response was found to double from 177.38kHz (ω₁) to 354.76kHz (2ω₁) from low-frequency cantilever (longer) to high-frequency cantilever (shorter). A plateau with a frequency ratio of 2.000, corresponding to a synchronisation region (also called as bandwidth), was observed and related to nonlinear vibration excited by driving power, which was also preliminarily discussed by using a discrete-element model. This shows the possibility of doubling the frequency response signal from the low-frequency cantilever to the high-frequency cantilever based on this superharmonic synchronisation.