Title: Raw data for "Comparison between Modelled and Measured Magnetic Field Scans of Different Planar Coil Topologies for Stress Sensor Applications"

Gibbs RM, Moreton G, Meydan T, et al. (2018). Raw data for "Comparison between Modelled and Measured Magnetic Field Scans of Different Planar Coil Topologies for Stress Sensor Applications". Cardiff University. http://doi.org/10.17035/d.2018.0046955726

Access Rights: Data can be made freely available subject to attribution

Access Method: Click to email a request for this data to opendata@cardiff.ac.uk

Dataset Details

Publisher: Cardiff University

Date (year) of data becoming publicly available: 2018

Coverage start date: 20/07/2017

Coverage end date: 26/10/2017

Data format: .csv, .aedt

Software Required: text editor or spreadsheet software, ANSYS software

Estimated total storage size of dataset: Less than 100 megabytes

Number of Files In Dataset: 14

DOI : 10.17035/d.2018.0046955726

DOI URL: http://doi.org/10.17035/d.2018.0046955726

The dataset consists of:

8 .csv files which can be read by any text editor or spreadsheet programme;
6 .aedt files which require ANSYS® Maxwell 3D FEM software (https://www.ansys.com/).

The .csv files are the output of scans of 4 topologies of Planar Coil made with the newly developed magnetic field imaging system. The .aedt are FEM models corresponding to each of these scans.

Planar coils are generally flat spirals of conductive track mounted on flexible polymer or PCB (printed circuit board) substrate. The shape, number of turns, width, and thickness of track can be varied. Other classes of planar coil are the meander and mesh coils, which do not spiral but alternate direction across the substrate with varying track thickness and displacement.

Four topologies of planar coil have been selected for investigation from, which, by convention, are called Circular, Mesh, Meander, and Square coils. The coils have been fabricated by CNC (computer numerically controlled) milling from a 54 mm × 30 mm FR4 PCB with a 35 μm thick copper layer and a track width of 0.5 mm. The dimensions and shape of each coil have been replicated as three-dimensional models within the ANSYS® Maxwell 3D FEM software (the .aedt models)

The three-dimensional magnetic field imaging system has been developed based on a Micromagnetics® STJ-020 tunneling magneto-resistance (TMR) sensor with a 2 μm × 4 μm active area, which has been refined to be a distance of 7.0 μm ± 0.5 μm from the tip edge. The sensor is mounted within a custom 3D-printed enclosure and attached to a Parker Automation based three-axis positioning arm with calibrated ±1 μm precision. The sample stage comprises a ThorLabs AMA027/M pitch and roll micrometer adjustable platform to allow the surface to be levelled before scanning. The safe distance of the tip over an uneven sample surface (5 μm ± 2.5 μm) and the refined tip edge give a practical minimum scan height z0 = 12 μm ± 3 μm.

The four planar coils were mounted on the sample stage and energized to draw 0.40 A ± 0.01 A of direct current using a PowerLine Electronics power supply.

Scans of a nominal 250 cells × 250 cells were performed with a cell size of 0.1 mm × 0.1 mm at the lowest scanning height sufficient to clear the solder points of the energizing connections. The STJ-020 TMR sensor outputs a potential difference proportional to the strength of magnetic field passing through its active area along the axis of the sensor. These voltage data are stored by the system within a three-dimensional matrix which has been output as a .csv file listing the three co-ordinates of the cell centre and the voltage in that cell. The voltage in each cell comprises the mean of 20 samples taken by the sensor. The STJ-020 TMR sensor potential differences (Volts) have been calibrated to field strength (Am−1) alongside a Lakeshore 475 DSP Gaussmeter probe within a long solenoid of varied energizing current. The linear calibration factor has been determined as 5.14 mV/Am−1 ± 3 μV/Am−1.

The .csv file contains 6 columns, with the column labels at the end of the file. The first three columns are the x,y,z coordinates of the centre of the cell in the unit of motor steps (4000 steps per mm). Columns 4 and 5 are for sensors which are not used in this instance. Column six contains the voltage value for the cell from the STJ-020 sensor, multiplied by 1.0e8 and stored as an integer.

To obtain the field strength in Am-1 for each cell you must multiply the value in column 6 by 1.941e-6

Information about the planar coils and the scan details is provided.

Research results based upon these data are published at http://doi.org/10.3390/s18040931


Finite-element modelling, Magnetic imaging, Planar Coils, Scanning, TMR sensor

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Last updated on 2018-12-07 at 14:16