Multilayer PCB planar fluxgate magnetic sensor

This paper presents two high sensitivity vector-2D magnetic sensors for low magnetic field measurements. The sensors, based on the double axis Fluxgate principle, are realized in PCB technology. The amorphous magnetic material Vitrovac 602SX (25 μm thick) was used as a ferromagnetic core for the sensors. For the first sensor the magnetic material was glued on top of the PCB structure with a bi-adhesive tape, while for the second sensor the magnetic material was placed between two PCB layers in the fabrication process. Applying a sinusoidal excitation current of 600 mA peak at 10 kHz, the magnetic sensitivity of the first sensor is about 1.68 mV/μT, suitable for detecting the Earth's magnetic field (±60 μT), while the linearity error is 1.55% full scale. Using the second sensor, a maximum sensitivity of about 0.28 mV/μT and a linearity error of about 1.35% full scale in the range of ±60 μT are obtained with the same sinusoidal excitation current of 600 mA peak at 10 kHz. The 2D vector sensors presented are characterized by a very simple fabrication process thanks to the use of commercially available thin ferromagnetic material. This make these sensors useful for low cost applications where small dimension are not crucial.