Amplitude saturation of MEMS resonators explained by autoparametric resonance

This article describes a phenomenon that limits the power handling of MEMS resonators. It is observed that above a certain driving level, the resonance amplitude becomes independent of the driving level. In contrast to previous studies of power handling in MEMS resonators it is found that this amplitude saturation cannot be explained by non-linear terms in the spring constant or electrostatic force. Instead we show that the amplitude in our experiments is limited by non-linear terms in the equation of motion which couple the in-plane length-extensional resonance mode to one or more out-of-plane bending modes. We present experimental evidence for the autoparametric excitation of these out-of-plane modes using a vibrometer. The measurements are compared to a modelwhich can be used to predict a power handling limit for MEMS resonators

Microphone

A microphone comprises a substrate (20), a microphone membrane (10) defining an acoustic input surface and a backplate (11) supported with respect to the membrane with a fixed spacing between the backplate (11) and the membrane (10). A microphone periphery area comprises parallel corrugations (24) in the membrane (10) and backplate (11). By using the same corrugated suspension for both the membrane and the backplate, the sensitivity to body noise is optimally suppressed

MEMS tunable capacitors and switches for RF applications

\u3cp\u3eRF MEMS capacitive switches and tunable capacitors have been realized in an industrialized thin-film process developed for manufacturing high-quality inductors and capacitors. Combining integrated passives with high-performance tuning and switching elements on the same die offers a potential for building a new generation of RF front-ends for hand-held mobile communication. Capacitive switches with an insertion loss of 0.4 dB and an isolation of 17 dB at 1 GHz have been demonstrated. Dual-gap relay type tunable capacitors have been fabricated that show a continuous and reversible tuning ratio of 12 together with a quality factor larger than 150 at frequencies higher than 0.5 GHz. These are the highest tuning ratio and quality factor reported to date. A 0-level packaging concept that is compatible with the fabrication technology has been adopted.\u3c/p\u3