Multi-gas sensing design based on nonlinear coupled micromachined resonators [Extended abstract]

Micro-electromechanical (MEMS) gas sensors receive increasing interest thanks to the high demand for environmental monitoring, air quality measurement, chemical process control, and personal safety. Extensive research has been conducted to improve the selectivity and sensitivity of gas sensors. However, there is still no comprehensive study on multi-gas sensing despite its potential. This work proposes a new prototype of gas sensors that can simultaneously detect the concentration of two different surrounding gases using a single structure based on a weakly coupled resonator. This study presents a thorough theoretical investigation on the dynamics of coupled cantilever and bridge resonators to prove its potential for multi-gas sensing. The sensing scheme relies on mass (due to gas absorption) and stiffness (due to cooling/heating) alteration of the cantilever and bridge resonators, respectively. A nonlinear theoretical model is developed using the Euler-Bernoulli beam theory while accounting for the geometric and electrostatic nonlinearities. The sensor's dynamic is explored using the Reduced-Order model and one-mode Galerkin discretization, showing its richness. The results suggest the potential of the nonlinear coupled resonator in performing muti-gas detection.