Steady-State and Transient Response of a Micromechanical Broadband Shoaling Amplifier

Abstract

An in-plane MEMS broadband shoaling motion amplitude amplifier based on a coupled mass-spring system is presented. It is shown how the amplification amplitude can be traded for the operational bandwidth by design. Three devices with different numbers of masses (three, five and seven), but all of them with the same total mass, were fabricated in silicon. The achieved baseline-amplification × bandwidth product ranges from 18.0 dB × 11.5 kHz for the seven mass device to 27.7 dB × 3.9 kHz for the three mass device. Transient recordings show amplification along the mass-spring-chain. The response time to reach the baseline amplification was found to be in the order of 10−4 s. This passive device can be used for ultra-low power structural and environmental monitoring (e.g., bridges, pipelines or rock-faces).

Keywords

• coupled mass-spring system
• micromechanical amplifier
• broadband
• shoaling
• acoustic emission sensing