Design and modeling of MEMS resonator for magnetic field sensing using hybrid actuation technique

A novel design of 0.751MHz MEMS resonant magnetic field sensor of mass 0.775pg based on hybrid actuation technique (Lorentz force and Electrostatic force) is presented and simulated using Coventor Ware and CADENCE simulators. The sensor consists of Aluminum paddle resonator, two supporting beams, driving electrodes, sensing electrode and silicon substrate with a capacitive CMOS readout amplifier. Working in a resonant condition, the sensor´s vibration amplitude is converted into the sensing capacitance change, which reflects the outside magnetic flux-density. Based on the simulation, the key structure parameters are optimized and the resonant frequency is estimated. The results of the device are in accordance with the theoretical results of the designed model. The resolution of the sensor is 1 nT. The results indicate its sensitivity more than 0.01 nV/nT, when operating at a normal atmosphere. The sensitivity and resolution can be enhanced through vacuum packaging.