Internal resonance of a U-shaped microresonator for gas sensing

In this work, we present an investigation into the 2:1 internal resonance and saturation phenomena in a compound micromachined U-shaped portal frame MEMS device and its potential exploitation for gas detection. The portal frame design accounts for the quadratic geometric nonlinearity, which yields mode coupling between the first and second modes of vibration of the structure. Experimental results are shown for the activation of the 2:1 internal resonance when varying the electrostatic loads or when exposing the structures to gases of various levels of viscosity. The experimental data are supported by the results of analytical and finite element models.