Active frequency tuning for magnetically actuated and piezoresistively sensed MEMS resonators

This letter, for the first time, reports an active frequency tuning for a magnetically actuated and piezoresistively sensed MicroElectroMechanical Systems resonator. Magnetic transduction is used to drive the device into the resonance. Piezoresistive transduction is used as resonance sensing technique and to tune the device's frequency by the Joule heating generated in the Wheatstone bridge without fabricating additional electrothermal heaters. The experiments are performed in air at room temperature and atmospheric pressure. The measurements shows that, by increasing the DC bias current of Wheatstone bridge from 0.5 to 5 mA, a maximum tuning range of -3403 ∼ ppm is achieved with a device resonating at 25.77 kHz.