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

Abstract 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.