Development of a Transient Magnetic Field Sensor Based on Digital Integration and Frequency Equalization

Transient magnetic field sensors are used in various electromagnetic environment measurement scenarios. In this paper, a novel magnetic field sensor based on a digital integrator was developed. The antenna was a small B-DOT loop. It was designed optimally for the simulation. The magnetic field signal was digitally integrated with the improved Al-Alaoui algorithm, resulting in less integration error. To compensate for the bandwidth loss of the optical fiber system, we specially designed an FIR (finite impulse response) filter for frequency compensation. The circuit was described, and the transimpedance amplifier was specially designed to ensure the low noise characteristic of the receiver. The sensitivity of the sensor was calibrated at 68.2 A·m−1/mV, the dynamic range was 50 dB (1–300 kA/m), the linear correlation coefficient was 0.96, and the bandwidth was greater than 100 MHz. It was tested and verified under the action of an A-type lightning current. The sensor exhibited high-precision performance and flat amplitude-frequency characteristics. Therefore, it is suitable for lightning positioning, partial discharge testing, electromagnetic compatibility management, and other applications.

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Adjustable Sensitivity MEMS Magnetic Sensor

Volume 4: 19th Design for Manufacturing and the Life Cycle Conference; 8th International Conference on Micro- and Nanosystems ◽

10.1115/detc2014-35004 ◽

2014 ◽

Author(s):

Sangtak Park ◽

Majed S. Al-Ghamdi ◽

Mahmoud Khater ◽

Eihab Abdel-Rahman ◽

Mustafa Yavuz

Keyword(s):

Magnetic Field ◽

Lorentz Force ◽

Dynamic Range ◽

Magnetic Sensor ◽

Magnetic Field Sensor ◽

Torsional Vibrations ◽

Experimental Demonstration ◽

Sensor Sensitivity ◽

Field Sensor ◽

Dc Bias

This paper introduces a novel MEMS magnetic field sensor based on the Lorentz force. It measures torsional vibrations excited via Lorentz force. The sensor sensitivity and dynamic range can be tuned by varying an electrostatic bias. Experimental demonstration shows that the sensor sensitivity can be changed from 0.7 (m/s)/T at 6 V DC bias to 1.4 (m/s)/T at 0 V DC bias.

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A Feedback Method to Improve the Dynamic Range and the Linearity of Magnetoimpedance Magnetic Sensor

Journal of Sensors ◽

10.1155/2019/2413408 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8

Author(s):

Dongfeng He

Keyword(s):

Magnetic Field ◽

Steel Plate ◽

Dynamic Range ◽

Magnetic Sensor ◽

Magnetic Field Sensor ◽

Amorphous Wire ◽

Alloy Plate ◽

Field Sensor ◽

Feedback Method ◽

The Magnetic Field

We developed a high-sensitivity magnetoimpedance magnetic field sensor using a FeCoSiB amorphous wire and a coil wound around it. The amorphous wire had the diameter of 0.1 mm and the length of 5 mm. The magnetic field resolution of about 20 pT/√Hz was achieved. But the dynamic range of the magnetoimpedance magnetic field sensor was only about ±0.7 Gauss, which was not enough for some applications, such as the defect evaluation of steel plate. The linearity of the system was also not good when big magnetic field was applied, which will cause some noise when the system is used in unshielded environment. We developed a feedback method to improve the dynamic range and the linearity of the magnetic field sensor. The operation point of the magnetic field sensor was fixed by sending a feedback current to the coil. Using the feedback method, the dynamic range was improved from ±0.7 Gauss to ±10 Gauss and the linearity was also improved over 100 times better. An eddy current testing system using the magnetic sensor was developed, and the crack defects in steel plate and in 3D-printed titanium alloy plate were evaluated.

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