{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,21]],"date-time":"2026-03-21T19:47:18Z","timestamp":1774122438586,"version":"3.50.1"},"reference-count":18,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2019,6,29]],"date-time":"2019-06-29T00:00:00Z","timestamp":1561766400000},"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>T-cell resonators have been used lately for non-invasive blood glucose measurements for photoacoustic spectroscopy on skin samples. A resonator has a significant role in determining the strength of the measured signal and the overall sensitivity of the sensor. Here we present results of the measurement of the photoacoustic signal of such a T-cell resonator. The signal is also modelled using the amplitude mode expansion method, which is based on eigenmode expansion and the introduction of losses in the form of loss factors. The measurement reproduced almost all the calculated resonances from the numerical models with fairly good agreement. The cause of the differences between the measured and the simulated resonances are explained. In addition, the amplitude mode expansion simulation model is established as a faster and computationally less demanding photoacoustic simulation alternative to the viscothermal model. The resonance frequencies from the two models differ by less than 1.8%. It is noted that the relative height of the amplitudes from the two models depends on the location of the antinodes within the different parts of the resonator. The amplitude mode expansion model provides a quick simulation tool for the optimization and design of macro resonators.<\/jats:p>","DOI":"10.3390\/s19132889","type":"journal-article","created":{"date-parts":[[2019,7,1]],"date-time":"2019-07-01T03:23:59Z","timestamp":1561951439000},"page":"2889","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Experimental and Numerical Investigation of a Photoacoustic Resonator for Solid Samples: Towards a Non-Invasive Glucose Sensor"],"prefix":"10.3390","volume":"19","author":[{"given":"Said","family":"El-Busaidy","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering and Production, Hamburg University of Applied Sciences, 20099 Hamburg, Germany"},{"name":"Mads Clausen Institute, University of Southern Denmark, 6400 S\u00f8nderborg, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bernd","family":"Baumann","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering and Production, Hamburg University of Applied Sciences, 20099 Hamburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0781-5248","authenticated-orcid":false,"given":"Marcus","family":"Wolff","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering and Production, Hamburg University of Applied Sciences, 20099 Hamburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lars","family":"Duggen","sequence":"additional","affiliation":[{"name":"Mads Clausen Institute, University of Southern Denmark, 6400 S\u00f8nderborg, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Henry","family":"Bruhns","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering and Production, Hamburg University of Applied Sciences, 20099 Hamburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,6,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"9616","DOI":"10.3390\/s91209616","article-title":"Photoacoustic techniques for trace gas sensing based on semiconductor laser sources","volume":"9","author":"Elia","year":"2009","journal-title":"Sensors"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"084901","DOI":"10.1063\/1.4816723","article-title":"Windowless ultrasound photoacoustic cell for in vivo mid-IR spectroscopy of human epidermis: Low interference by changes of air pressure, temperature, and humidity caused by skin contact opens the possibility for a non-invasive monitoring of glucose in the interstitial fluid","volume":"84","author":"Pleitez","year":"2013","journal-title":"Rev. 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Available online: https:\/\/www.mathworks.com."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/13\/2889\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:02:28Z","timestamp":1760187748000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/13\/2889"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,6,29]]},"references-count":18,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2019,7]]}},"alternative-id":["s19132889"],"URL":"https:\/\/doi.org\/10.3390\/s19132889","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,6,29]]}}}