A micromachined square extensional mode resonant magnetometer with directly voltage output

In this paper, a novel resonant magnetometer is demonstrated based on MEMS Technology. The proposed sensor consists of a square extensional mode resonator with a planar induction coil placed on top of the resonant plate. The sensor employs capacitive driving and electromagnetic induction to detect external magnetic field through the electromotive force in the induction coil. The operation principle, fabrication process as well as the measurement of the magnetic field sensor is demonstrated. Experimental result shows that the device offers a sensitivity of 3 μV/mT at its resonant frequency of f₀ = 4.33 MHz in atmosphere pressure.