A two-axis sensing mems magnetometer with monolithic moving parts in orthogonal resonance order

This paper reports a two-axis sensing micro-electromechanical system (MEMS) magnetometer, which features an electromagnetic inductor on an electrostatically driven eccentric resonator. Our sensor utilizes electrostatic force for driving and electromagnetic induction for sensing. This sensor offers advantages, such as eliminating self-heating and acquiring direct output of induced voltage. Also, we designed a monolithic eccentric structure that consists of an asymmetric inner mass with an outer mass, leading to two torsional resonance modes with orthogonal directions. By electrostatically driving the eccentric moving part at the resonant frequency of each mode, we achieved X-axis or Y-axis magnetic field sensing capability without complex integration in multi-sensing.