Inverse Eigenvalue Sensing in Coupled Micro/Nano System

Micro/nano resonators are extensively used for sensing. Coupled arrays of such sensors can enhance functionality, sensitivity, and accuracy. Sensing can be performed using either the eigenvalue or eigenvector. The eigenvalue method utilizes the frequency shift after a change in the mass/stiffness, while the eigenvector method measures the amplitude ratio change of these resonators at different modes. However, none of these methods fully utilizes the eigen-information provided by the coupled system. Here, we present an inverse eigenvalue sensing (IES) approach using an example of two coupled micro resonators. By using eigenfrequencies from one resonator only, IES enables single-input-single-output actuation and hence reduces the readout complexity. Furthermore, it provides full parameter extraction capability to determine mass/stiffness and coupling ratio with enhanced accuracy, dynamic range, and linearity. Experimental results demonstrate a relative error as low as
$2\times 10^{-5}$
and a dynamic range of 66 dB. Analytical and Monte Carlo analysis have also been performed to determine the sensing limit. [2017-0265]