Two-Axis, Miniature Fluxgate Sensors (original) (raw)
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Design and Characterization of a Family of Fluxgate Magnetic Sensors in PCB Technology
Sensors and Microsystems, 2005
Fluxgates magnetic sensors are the most suitable magnetic sensors for applications requiring a resolution down to 0.1 nT and an absolute precision in the order of 1 nT. For consumer applications the trade-off between cost and performance can be optimized by using fluxgate sensors realized with printed circuit board (PCB) technology. In this work, a family of planar single and dual axis fluxgate sensors realized in PCB technology, featuring a sensitivity suitable for detecting the earth's magnetic field, is presented and experimentally characterized. The proposed sensors achieve a magnetic sensitivity of about 0.46 mV/µT and 0.35 mV/µT for a single and double axis structure respectively.
An Integrated Micro-Fluxgate Magnetic Sensor With Front-End Circuitry
IEEE Transactions on Instrumentation and Measurement, 2009
In this paper, a double-axis planar micro-Fluxgate magnetic sensor and its front-end circuitry are presented. The ferromagnetic core material, i.e., the Vitrovac 6025 X, has been deposited on top of the coils with the dc-magnetron sputtering technique, which is a new type of procedure with respect to the existing solutions in the field of Fluxgate sensors. This procedure allows us to obtain a core with the good magnetic properties of an amorphous ferromagnetic material, which is typical of a core with 25-μm thickness, but with a thickness of only 1 μm, which is typical of an electrodeposited core. The micro-Fluxgate has been realized in a 0.5-μm CMOS process using copper metal lines to realize the excitation coil and aluminum metal lines for the sensing coil, whereas the integrated interface circuitry for exciting and reading out the sensor has been realized in a 0.35-μm CMOS technology. Applying a triangular excitation current of 18 mA peak at 100 kHz, the magnetic sensitivity achieved is about 10 LSB/μT [using a 13-bit analog-to-digital converter (ADC)], which is suitable for detecting the Earth's magnetic field (±60 μT), whereas the linearity error is 3% of the full scale. The maximum angle error of the sensor evaluating the Earth magnetic field is 2 • . The power consumption of the sensor is about 13.7 mW. The total power consumption of the system is about 90 mW.
New hybrid technology for planar fluxgate sensor fabrication
IEEE Transactions on Magnetics, 1999
We have adapted a new printed circuit board (PCB) technology to the fabrication of ultraflat and sensitive fluxgate magnetic field sensors. The two outer layers of the PCB stack compose the electrical windings of fluxgates, while the inner layer is made of a micro-patterned amorphous magnetic ribbon with extremely high relative magnetic permeability (r 100 000). Two basic configurations were considered: one based on a toroidal magnetic core and the other on a rectangular core with and without an air gap. The field response and sensitivity of the fluxgate devices have been studied as a function of the gap length, the excitation current, and excitation frequency. Compared to fluxgate sensors of similar size, a relatively high sensitivity of 60 V/T was found at 30 kHz for a five-winding detection coil wound around a rectangular E-shaped magnetic core. This high performance is primarily attributable to the high-permeability magnetic core. The results clearly show the potential of this fluxgate device for application as a magnetic sensor.
An Integrated Micro-Fluxgate Magnetic Sensor with Sputtered Ferromagnetic Core
2006
In this paper a double axis planar micro-Fluxgate magnetic sensor is presented. The ferromagnetic core material, the Vitrovac 6025 X, has been deposited on top of the coils with the DC-magnetron sputtering technique, a new type of procedure with respect the existing solutions in the field of Fluxgate sensor. This procedure allows us to obtain a core with the good magnetic properties of the amorphous ferromagnetic material, typical of a core 25 mum thick, but with a thickness of only 1 mum, typical of a core electrodeposited. The micro-Fluxgate has been realized in a 0.5 mum CMOS process using copper metal lines to realize the excitation coil and aluminum metal lines for the sensing coils. Applying a triangular excitation current of 18 mA peak at 100 kHz the magnetic sensitivity achieved is about 0.45 mV/muT, suitable for detecting the Earth's magnetic field (plusmn50 muT), while the linearity error is 1.15% of the full scale. The maximum angle error of the sensor, evaluating the Earth magnetic field, is 3.4deg. The power consumption of the sensor is about 13.7 mW
Planar fluxgate sensor with an electrodeposited amorphous core
Sensors and Actuators A-physical, 2004
We have combined the printed circuit board (PCB) technology with the electrodeposition of amorphous ferromagnetic Co-P alloys to produce a new 2D fluxgate sensor. The fabrication procedure avoids the use of glue to integrate the core in the device, which improves its performance and makes the production process more reproducible. Choosing properly the frequency and amplitude of the driving current, high sensitivity (160 V/T) or a large linear range (0-250 T) can be achieved. The use of electrodeposited amorphous Co-P opens new perspectives to improve the performances of inductive microdevices as fluxgates, inductors and transformers.
Optimization of the magnetic properties of materials for fluxgate sensors
Materials Research-ibero-american Journal of Materials, 2008
A study was made of the variation of the magnetic properties of cobaltbased alloys using different compositions of CoFeSiB and CoFeSiBCr systems, which were produced by the meltspinning technique and some of them subjected to a stress annealing treatment. A comparative study of core geometry and supporting material was also performed in order to obtain low noise fluxgate sensor core using amorphous magnetic ribbons of these alloys. The best alloy was a stress annealed Co67.5Fe3.5Si17.4B11.6 sample, which yielded fluxgate sensors with lower noise levels than those of commercial crystalline materials.
Acta Physica Polonica A, 2017
Fluxgate magnetic field sensors are commonly used in the industry, navigation as well as in non-destructive testing. Moreover, recent development of such sensors is focused on effective application of thin layer magnetic cores, such as made of amorphous alloys. However, effective development of fluxgate sensors require method of modeling its core taking into account demagnetization. The paper presents the results of optimization of the shape of thin-layer core for fluxgate sensor. Due to the fact that possibility of application of finite elements method is limited in the case of thin layer, the method of moments was used. Considering the geometry of the core as well as magnetizing and sensing winding, the optimal proportion of the length/thickness parameter was determined from the point of view of sensor sensitivity. It was proven that value of this optimal proportion is strongly dependent of thickness of the core.
Fluxgate magnetic sensor and front-end circuitry in an integrated microsystem
Sensors and Actuators A-physical, 2006
A complete vector-2D micro-integrated sensors system for magnetic field measurement is proposed. The system consists of a micro-integrated Fluxgate magnetometer with front-end electronic circuitry based on second-harmonic detection. The magnetic core of the sensor is the VITROVAC 6025X deposited over the micro-integrated coils with the RF magnetron sputtering process deposition.
Study on Micro Fluxgate Magnetic Sensor
Based on MEMS technology, a novel type of micro fluxgate magnetic sensor (MFGM), which exploits magnetic fluxgate principle, has been designed. It has symmetrical geometry, and is flexible for electrical connection, easy to form as a two-axis or a one-axes vector sensor. MFGM is easily assembled into a 3-axis subminiature magnetometer and can be applied to measure vector of the weak geomagnetic field. The microfabrication process has been developed. The UV lithography technology in combination with thick negative and positive photoresists is exploited in the microfabrication. The original samples have been produced with the dimension of 1 cm × 1 cm × 100 um . MFGM can be widely applied in the conventional and potential fields, for examples, scientific research, automation, process control of industry, mineral prospecting, medical appliance, especially in micro-satellite (including nano-satellite and pico-satellite) missions. It is a important part of Attitude Determination and Control System (ADCS) subsystem of MEMSSat-1 pico-satellite (researched by Tsinghua Univ.), used to obtain information about the attitude of the satellite individually or in combination with other parts such as Micro Inertial Measurement Unit (MIMU).