Parametrically Amplified $Z$-Axis Lorentz Force Magnetometer

Abstract

This paper describes a microelectromechanical systems (MEMS) Lorentz force navigation magnetometer whose fabrication is fully compatible with existing foundry processes used to manufacture MEMS inertial sensors. Operating at 1 atm, the magnetometer is shown to have a Brownian-noise-limited field resolution of 87 nT/√Hz and a corresponding angular resolution of 0.7°/√Hz. To achieve Brownian-noise-limited performance at 1 atm, parametric amplification was performed which amplifies the Lorentz force 40% more than the Brownian noise force and increases the field sensitivity of the device up to 82.5 folds. Here, the parametric signal is also used to perform electromechanical amplitude modulation to mitigate capacitive feedthrough of the drive signal to the sensing electronics.