Stable oscillation of mems resonators beyond the critical bifurcation point

Abstract

MEMS resonators have many useful features, but they can suffer performance limitations because of the limited linear range of motion of their micromechanical elements. Operation beyond the critical bifurcation limit is believed to cause significant instabilities and is generally discouraged [1]. However, the stability criterion for closed-loop oscillators differs from that for open-loop observation [2], thereby enabling operation of stable oscillators beyond the limit dictated by critical bifurcation. This paper describes the use of phase-controlled oscillators to prove stable operation beyond the critical bifurcation limit, which can directly improve the power handling capabilities of many micromechanical oscillators.