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 6025X (25 mu m 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/mu T, suitable for detecting the Earth's magnetic field (+/- 60 mu T), while the linearity error is 1.55% full scale. Using the second sensor, a maximum sensitivity of about 0.28 mV/mu T and a linearity error of about 1.35% full scale in the range of +/- 60 mu T 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.