Quantitative Identification Scheme for Multiple Analytes With a Mode-Localized Cantilever Array

This work proposes an identification scheme for two different analytes using a coupled three-cantilever array. In this scheme, for the first time, we put forward two key parameters including the localization degree X_k and norm of normalized eigenmode shifts |Δu| to make qualitative and quantitative identification of mixed target analytes, respectively. Theoretical results, which have been verified by numerous simulations, indicate that the linear range (i.e., localization degree with respect to mass ratio) of this mass identification can reach approximately two orders of degree. Besides, we also studied the effect of the coupling factor on the resonance frequency and also proposed that the coupling factor possessed a lower limit to guarantee the resolution of mass sensing in either low vacuum environment or ambient pressure. Last but not least, this scheme could extend to identify analytes as many as possible in a confined space or certain sorts of analytes with a structure as simple as possible, which contributes to the application of gas sensors.

I. Introduction

Micro-resonator sensor is used to detect external stimulus, such as mass perturbation [1]–[6] or stiffness perturbation [7]–[10]. The amount of relative shifts in the sensor’s vibration characteristics is measured to detect the induced perturbation. If the amount of changes can be enhanced by certain amplification mechanism, ultimate sensing can be achieved, and furthermore the slight mass or stiffness perturbation can be detected. One way to enhance the sensing sensitivity is to weakly couple several resonators based on mode localization [2]–[8]. This phenomenon was firstly predicted by Anderson’s Nobel Prize winning work. Those coupled resonator sensors based on mode localization can be termed as mode-localized sensors.