Mode-Localized Z-Axis Accelerometer

Exploring the integration of in-plane and out-of-plane accelerometers is a significant research focus, with a primary challenge lying in the development of a precise
${Z}$
-axis accelerometer. Although mode localization has been successfully applied to in-plane accelerometers, its application to
${Z}$
-axis accelerometers remains challenging. This article presents the innovative design of a mode-localized
${Z}$
-axis accelerometer based on a weakly coupled resonator (WCR) system. A seesaw structure is employed to translate the tested
${Z}$
-axis acceleration into variations in the capacitor overlap area, inducing stiffness change of one resonator. The mode-localization phenomenon is triggered and the
${Z}$
-axis acceleration can be determined through the amplitude of two resonators. The specifications of the
${Z}$
-axis accelerometer are impressive, with a sensitivity of 9.48/g, noise floor of
$6.03~\mu \text{g} / \surd $
Hz, and bias instability of
$10.03~\mu \text{g}$
. This article presents a new method for measuring out-of-plane acceleration and has the potential to be integrated with in-plane mode-localized accelerometers.