100 nT/√Hz, 0.5 mm² monolithic, multi-loop low-power 3-axis MEMS magnetometer

Abstract

The work proposes the first monolithic, 3-axis, multi-loop MEMS Lorentz-force magnetometer. The sensor is studied to be compatible for 6-degrees-of-freedom (DOF), all-MEMS combos (with a 3-axis accelerometer), and more convenient in terms of cost/area than hybrid solutions. The structure exploits an innovative geometry, which enables - though using 10 current-recirculating loops as a Lorentz-force multiplicative factor - to combine in a single device the sensitivity along all three sensing axes. This in turn generates an 8-fold active area reduction in the magnetic sensor, while halving noise density down to 100 nT/√Hz, with respect to previous solutions based on multi-loop architecture.