Performance Degradation Effect Countermeasures in Residence Times Difference (RTD) Fluxgate Magnetic Sensors

Abstract

This paper aims to explore the detection defect of residence times difference (RTD) fluxgate working in low-power mode. It presents the countermeasures for sensor resolution improvement and linearity enhancement. The main defects are amplitude and symmetry changes induced in the output spikes of fluxgate probe due to the magnetic field. These defects lead to thresholds deviation and asymmetry, then causes severe performance degradation especially on detection resolution and linearity according to the RTD theory. To overcome such effects, the optimized RTD method based on voltage extraction and feedback technology is proposed to implement magnetic field compensation and achieve a zero-field running regime of the RTD fluxgate. In this regard, the sensor linearity is improved by a factor of 38, and the resolution degradation effect is suppressed more than 6 times, verified by the laboratory experiments. The optimized detection method proposed in this paper demonstrated a great potential to achieve lower power consumption, will make the RTD fluxgate more promising technology among bio-magnetic applications.

Magnetic Crosstalk Suppression and Probe Miniaturization of Coupled Core Fluxgate Sensors

“…Nowadays, we have found there are some detection defects in residence times differences fluxgate. And we have found the field compensation by feedback technology can solve this degradation [14]. This newly proposed CCFM probe with VA structure in this paper has potential to implement field compensation, because all the fluxgate elements are installed along the same axis.…”

Design and Implementation of Close-loop Detection for Coupled Core Fluxgate Magnetic Sensors

“…The nonzero magnetic field can give rise to output nonlinearity, sensitivity limitation, and frequency change. These undesired effects will cause sensor accuracy degradation [16] and increase the complexity of injection locking, which can effectively reduce the sensor noise floor [17,18] If the CCFM is working at a zero magnetic field during its operation, these degradations will vanish. Based on this fact, the feedback system with modified RTD detection method to achieve a zero magnetic field running regime of CCFM.…”

“…According to our recent experiments, the sensor output linearity and sensitivity are constrained by the external magnetic field in the residence times difference (RTD) readout strategy [16]. And the frequency of the self-oscillation is also influenced by the external magnetic field, which makes injection locking (effective method to reduce noise floor) challenging to implement.…”

Recent Progress of Fluxgate Magnetic Sensors: Basic Research and Application

“…Compared with other magnetic sensors, fluxgate magnetic sensors have advantages such as high sensitivity, high accuracy, high resolution, simple and compact structures, and low noise [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. What’s more, they can be used in different kinds of environment and even hostile environments, and they have important applications in weak magnetic field measurements.…”