{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:21:11Z","timestamp":1760242871386,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2016,12,31]],"date-time":"2016-12-31T00:00:00Z","timestamp":1483142400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Interdigitated dielectrometry sensors (IDS) are capacitive sensors investigated to precisely measure the relative permittivity (     \u03f5 r     ) of insulating liquids. Such liquids used in the power industry exhibit a change in      \u03f5 r      as they degrade. The IDS ability to measure      \u03f5 r      in-situ can potentially reduce maintenance, increase grid stability and improve safety. Noise from external electric field sources is a prominent issue with IDS. This paper investigates the novelty of applying a Faraday cage onto an IDS as a 3D shield to reduce this noise. This alters the spatially distributed electric field of an IDS affecting its sensing properties. Therefore, dependency of the sensor\u2019s signal with the distance to a shield above the IDS electrodes has been investigated experimentally and theoretically via a Green\u2019s function calculation and FEM. A criteria of the shield\u2019s distance s =      s 0      has been defined as the distance which gives a capacitance for the IDS equal to      1   \u2212     e  \u2212 2   = 86.5 %     of its unshielded value. Theoretical calculations using a simplified geometry gave a constant value for      s 0     \/   \u03bb    = 1.65, where    \u03bb    is the IDS wavelength. In the experiment, values for      s 0      were found to be lower than predicted as from theory and the ratio      s 0     \/   \u03bb    variable. This was analyzed in detail and it was found to be resulting from the specific spatial structure of the IDS. A subsequent measurement of a common insulating liquid with a nearby noise source demonstrates a considerable reduction in the standard deviation of the relative permittivity from      \u03c3  unshielded   = \u00b1    9.5% to      \u03c3  shielded   = \u00b1    0.6%. The presented findings enhance our understanding of IDS in respect to the influence of a Faraday shield on the capacitance, parasitic capacitances of the IDS and external noise impact on the measurement of      \u03f5 r     .<\/jats:p>","DOI":"10.3390\/s17010077","type":"journal-article","created":{"date-parts":[[2017,1,2]],"date-time":"2017-01-02T09:54:18Z","timestamp":1483350858000},"page":"77","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["A 3D Faraday Shield for Interdigitated Dielectrometry Sensors and Its Effect on Capacitance"],"prefix":"10.3390","volume":"17","author":[{"given":"Alex","family":"Risos","sequence":"first","affiliation":[{"name":"School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington 6012, New Zealand"},{"name":"Robinson Research Institute, Victoria University of Wellington, Lower Hutt 5010, New Zealand"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2412-0683","authenticated-orcid":false,"given":"Nicholas","family":"Long","sequence":"additional","affiliation":[{"name":"Robinson Research Institute, Victoria University of Wellington, Lower Hutt 5010, New Zealand"}]},{"given":"Arvid","family":"Hunze","sequence":"additional","affiliation":[{"name":"Robinson Research Institute, Victoria University of Wellington, Lower Hutt 5010, New Zealand"}]},{"given":"Gideon","family":"Gouws","sequence":"additional","affiliation":[{"name":"School of Engineering and Computer Sciences, Victoria University of Wellington, Wellington 6012, New Zealand"}]}],"member":"1968","published-online":{"date-parts":[[2016,12,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1109\/MEI.2013.6585853","article-title":"50 years in the development of insulating liquids","volume":"29","author":"Fofana","year":"2013","journal-title":"IEEE Electr. 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