A Piezoelectric Resonant Accelerometer for Above 140db Linear Dynamic Range High-G Applications

Abstract

This paper reports on the design, fabrication and characterization of ultra-high linear dynamic range frequency-output resonant accelerometer with wide bandwidth utilizing a novel area-changing electrostatic frequency modulation (ACE-FM) mechanism. The accelerometer consists of a piezoelectrically-actuated free-free-beam resonator implemented in the device layer of an SOI wafer, and a high-stiffness proof-mass in the handle layer, separated from the resonator by a uniform sub-micron gap. Fabricated devices measure 850μg/√Hz VRW and 3milli-g BI with projected linear dynamic range greater than 140dB for accelerations up to 50,000g in a single-ended output configuration. Improved frequency stability can be achieved using differential outputs, which provides a path to realizing 180dB linear dynamic range in a microscale accelerometer for demanding applications including seismometers and aerospace.