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A 3-Axis Miniature Magnetic Sensor Based on a Planar Fluxgate Magnetometer with an Orthogonal Fluxguide.

Lu CC, Huang J - Sensors (Basel) (2015)

Bottom Line: Experimental characterization of the miniature fluxgate device demonstrates satisfactory spatial magnetic field detection results in terms of responsivity and noise spectrum.As a result, at an excitation frequency of 50 kHz, a maximum in-plane responsivity of 122.4 V/T appears and a maximum out-of-plane responsivity of 11.6 V/T is obtained as well.The minimum field noise spectra are found to be 0.11 nT/√Hz and 6.29 nT/√Hz, respectively, in X- and Z-axis at 1 Hz under the same excitation frequency.

View Article: PubMed Central - PubMed

Affiliation: Institute of Mechatronic Engineering, National Taipei University of Technology, Taipei 106, Taiwan. cclu23@ntut.edu.tw.

ABSTRACT
A new class of tri-axial miniature magnetometer consisting of a planar fluxgate structure with an orthogonal ferromagnetic fluxguide centrally situated over the magnetic cores is presented. The magnetic sensor possesses a cruciform ferromagnetic core placed diagonally upon the square excitation coil under which two pairs of pick-up coils for in-plane field detection are allocated. Effective principles and analysis of the magnetometer for 3-D field vectors are described and verified by numerically electromagnetic simulation for the excitation and magnetization of the ferromagnetic cores. The sensor is operated by applying the second-harmonic detection technique that can verify V-B relationship and device responsivity. Experimental characterization of the miniature fluxgate device demonstrates satisfactory spatial magnetic field detection results in terms of responsivity and noise spectrum. As a result, at an excitation frequency of 50 kHz, a maximum in-plane responsivity of 122.4 V/T appears and a maximum out-of-plane responsivity of 11.6 V/T is obtained as well. The minimum field noise spectra are found to be 0.11 nT/√Hz and 6.29 nT/√Hz, respectively, in X- and Z-axis at 1 Hz under the same excitation frequency. Compared with the previous tri-axis fluxgate devices, this planar magnetic sensor with an orthogonal fluxguide provides beneficial enhancement in both sensory functionality and manufacturing simplicity. More importantly, this novel device concept is considered highly suitable for the extension to a silicon sensor made by the current CMOS-MEMS technologies, thus emphasizing its emerging applications of field detection in portable industrial electronics.

No MeSH data available.


Related in: MedlinePlus

A schematic diagram of the fluxgate magnetometer setup for characterization measurement.
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sensors-15-14727-f008: A schematic diagram of the fluxgate magnetometer setup for characterization measurement.

Mentions: Device characteristics of the proposed fluxgate sensor are implemented by a measurement system shown in Figure 8. The system is able to perform the second-harmonic detection and generate external magnetic fields from an ac modulated solenoid. Basically the measurement system includes a power amplifier (BA4825, NF Corp., Yokohama, Japan), a lock-in amplifier (SR830, Stanford Research Systems, Sunnyvale, CA, USA), a signal pre-amplifier (SR560, Stanford Research Systems), a function generator and a digital oscilloscope. In practice, the second harmonics are generated from the planar pick-up coils and exhibited by the lock-in amplifier using a phase-reference method. Therefore, the sensitivity, or known as responsivity (dV/dB), of the fabricated magnetometer can be fully defined and evaluated by recording the magnitudes of the pick-up voltage and magnetic fields via these instruments.


A 3-Axis Miniature Magnetic Sensor Based on a Planar Fluxgate Magnetometer with an Orthogonal Fluxguide.

Lu CC, Huang J - Sensors (Basel) (2015)

A schematic diagram of the fluxgate magnetometer setup for characterization measurement.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507702&req=5

sensors-15-14727-f008: A schematic diagram of the fluxgate magnetometer setup for characterization measurement.
Mentions: Device characteristics of the proposed fluxgate sensor are implemented by a measurement system shown in Figure 8. The system is able to perform the second-harmonic detection and generate external magnetic fields from an ac modulated solenoid. Basically the measurement system includes a power amplifier (BA4825, NF Corp., Yokohama, Japan), a lock-in amplifier (SR830, Stanford Research Systems, Sunnyvale, CA, USA), a signal pre-amplifier (SR560, Stanford Research Systems), a function generator and a digital oscilloscope. In practice, the second harmonics are generated from the planar pick-up coils and exhibited by the lock-in amplifier using a phase-reference method. Therefore, the sensitivity, or known as responsivity (dV/dB), of the fabricated magnetometer can be fully defined and evaluated by recording the magnitudes of the pick-up voltage and magnetic fields via these instruments.

Bottom Line: Experimental characterization of the miniature fluxgate device demonstrates satisfactory spatial magnetic field detection results in terms of responsivity and noise spectrum.As a result, at an excitation frequency of 50 kHz, a maximum in-plane responsivity of 122.4 V/T appears and a maximum out-of-plane responsivity of 11.6 V/T is obtained as well.The minimum field noise spectra are found to be 0.11 nT/√Hz and 6.29 nT/√Hz, respectively, in X- and Z-axis at 1 Hz under the same excitation frequency.

View Article: PubMed Central - PubMed

Affiliation: Institute of Mechatronic Engineering, National Taipei University of Technology, Taipei 106, Taiwan. cclu23@ntut.edu.tw.

ABSTRACT
A new class of tri-axial miniature magnetometer consisting of a planar fluxgate structure with an orthogonal ferromagnetic fluxguide centrally situated over the magnetic cores is presented. The magnetic sensor possesses a cruciform ferromagnetic core placed diagonally upon the square excitation coil under which two pairs of pick-up coils for in-plane field detection are allocated. Effective principles and analysis of the magnetometer for 3-D field vectors are described and verified by numerically electromagnetic simulation for the excitation and magnetization of the ferromagnetic cores. The sensor is operated by applying the second-harmonic detection technique that can verify V-B relationship and device responsivity. Experimental characterization of the miniature fluxgate device demonstrates satisfactory spatial magnetic field detection results in terms of responsivity and noise spectrum. As a result, at an excitation frequency of 50 kHz, a maximum in-plane responsivity of 122.4 V/T appears and a maximum out-of-plane responsivity of 11.6 V/T is obtained as well. The minimum field noise spectra are found to be 0.11 nT/√Hz and 6.29 nT/√Hz, respectively, in X- and Z-axis at 1 Hz under the same excitation frequency. Compared with the previous tri-axis fluxgate devices, this planar magnetic sensor with an orthogonal fluxguide provides beneficial enhancement in both sensory functionality and manufacturing simplicity. More importantly, this novel device concept is considered highly suitable for the extension to a silicon sensor made by the current CMOS-MEMS technologies, thus emphasizing its emerging applications of field detection in portable industrial electronics.

No MeSH data available.


Related in: MedlinePlus