Development and analysis of a PCB vector 2-D magnetic field sensor system for electronic compasses

A high-sensitivity vector two-dimensional (2-D) magnetic sensor system for low magnetic field measurements has been realized and tested. The system, made in PCB technology, consists of a double-axis Fluxgate magnetic sensor and the readout electronic circuitry, based on second-harmonic detection. The amorphous magnetic materials Vitrovac 6025X (25 μm thick) and Vitrovac 6025Z (20 μm thick) were used as the ferromagnetic core of the sensor. By applying a sinusoidal excitation current having a 450-mA peak at 10 kHz with Vitrovac 6025Z, the measured magnetic sensitivity was about 1.25 mV/μT. This value seems to be adequate for the Earth´s magnetic field detection (±60 μT). The full-scale linearity error was about 1.5%. By using the thicker Vitrovac 6025X and a sinusoidal excitation current having a 600-mA peak at 10 kHz, a maximum sensitivity of approximately 1.68 mV/μT with a linearity error of about 1.55% full scale in the range of ±60 μT were measured. Due to the use of commercially available ferromagnetic materials, the vector 2-D magnetic sensor system presented is characterized by a very simple fabrication process, thus allowing low-cost devices to be designed.