Development and comparative analysis of fluxgate magnetic sensor structures in PCB technology

In this paper, we present a family of fluxgate magnetic sensors on printed circuit boards (PCBs), suitable for an electronic compass. This fabrication process is simple and inexpensive and uses commercially available thin ferromagnetic materials. We developed and analyzed the prototype sensors with software tools based on the finite-element method. We developed both single- and double-axis planar fluxgate magnetic sensors as well as front-end circuitry based on second-harmonic detection. Two amorphous magnetic materials, Vitrovac 6025X (25 [micro]m thick) and Vitrovac 6025Z (20 [micro]m thick), were used as the ferromagnetic core. We found that the same structures can be made with Metglas ferromagnetic core. The double-axis fluxgate magnetic sensor has a sensitivity of about 1.25 mV/[micro]T with a linearity error of 1.5% full scale, which is suitable for detecting Earth's magnetic field ([+ or -]60 [micro]T full-scale) in an electronic compass. Index Terms--Amorphous magnetic material, electronic compass, magnetic sensor, planar fluxgate sensor.