Pick-up coil free gating-flux magnetometers powered by differential excitation signals

• Published in: Journal of magnetism and magnetic materials Vol. 527; p. 167790
• Main Authors: Luong, Van Su, Pham, Thi-Hoa
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2021; Elsevier BV
• Subjects: Bridge loads; Circuits; Excitation; Excitation coil; Fluxgate magnetometers; Fluxgate sensors; Magnetic cores; Magnetic fields; Magnetic sensors; Magnetometers; Noise levels; Pickup coils; Sensitivity; Excitation coil; Magnetometers; Magnetic sensors; Fluxgate sensors
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2021.167790

•The modified sensor uses an excitation bridge without a pick-up coil.•The excitation bridge directly detects the external magnetic field.•The significant sensitivity of 629 V/T is achieved.•The integration capability of the fluxgate sensor is improved.•Many sensing features of the conventional fluxgate sensors are maintained. This work presents a simple structure of a fluxgate sensor with superior characteristics, using an excitation-bridge coil without the need of a conventional pick-up coil. The proposed device is characterized by the dual role of the excitation coil, which serves both to magnetize the soft magnetic core periodically and to pick-up the external magnetic fields simultaneously. In fulfilling such roles, the excitation coil is designed in two-rod cores and configured into two branches of an anti-serial circuit. Each branch is combined with an external resistance to forming an excitation-bridge circuit that induces a differential signal proportional to the external magnetic fields. The experimental results demonstrate a significant sensitivity of 629 mV/mT and a noise level of 320pT/√Hz@1Hz. The proposal has many merits without the pick-up coil, including simplified integration, miniature size, and high sensitivity.