The effects of pressure on micromechanical air-filled cavities made by a pair of suspended, parallel silicon nitride membranes are investigated in the free molecular and quasi-molecular regimes. Variations of the fundamental drummode mechanical resonant frequencies and damping with air pressure are determined by means of optical interferometry. A kinetic damping linear friction force and a positive resonant frequency shift due to the compression of the fluid between the membranes are observed to be proportional with pressure in the range 0.01-10 mbars. For resonators with near-degenerate modes hybridization of the modes due to this squeeze film effect is also observed and well accounted for by a simple spring-coupled oscillator model.
@article{arxiv.1710.00043,
title = {Effects of pressure on suspended micromechanical membrane arrays},
author = {Andreas Naesby and Sepideh Naserbakht and Aurélien Dantan},
journal= {arXiv preprint arXiv:1710.00043},
year = {2017}
}