{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,28]],"date-time":"2026-03-28T09:00:32Z","timestamp":1774688432426,"version":"3.50.1"},"reference-count":24,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2018,10,12]],"date-time":"2018-10-12T00:00:00Z","timestamp":1539302400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Agencia Estatal de Investigaci\u00f3n and FEDER","award":["TEC2016-77242-C3-1-R AEI\/FEDER, UE"],"award-info":[{"award-number":["TEC2016-77242-C3-1-R AEI\/FEDER, UE"]}]},{"name":"Comunidad de Madrid (SINFOTON-CM)","award":["P2013\/MIT-2790"],"award-info":[{"award-number":["P2013\/MIT-2790"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Wireless communication is growing quickly and now allows technologies like the Internet of Things (IoT). It is included in many smart sensors helping to reduce the installation and system costs. These sensors increase flexibility, simplify deployment and address a new set of applications that was previously impossible with a wired approach. In this work, a wireless temperature sensor based on a nematic liquid crystal as variable capacitance is proposed as a proof of concept for potential wearable applications. Performance analysis of the wireless temperature sensor has been carried out and a simple equivalent circuit has been proposed. Sensor prototype has been successfully fabricated and demonstrated as the beginning of new biomedical sensors.<\/jats:p>","DOI":"10.3390\/s18103436","type":"journal-article","created":{"date-parts":[[2018,10,15]],"date-time":"2018-10-15T03:43:01Z","timestamp":1539574981000},"page":"3436","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Wireless Temperature Sensor Based on a Nematic Liquid Crystal Cell as Variable Capacitance"],"prefix":"10.3390","volume":"18","author":[{"given":"Juan Carlos","family":"Torres","sequence":"first","affiliation":[{"name":"Displays and Photonic Applications Group (GDAF-UC3M), Electronic Technology Department, Carlos III University of Madrid, Av de la Universidad 30, E28911 Legan\u00e9s, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1231-0570","authenticated-orcid":false,"given":"Braulio","family":"Garc\u00eda-C\u00e1mara","sequence":"additional","affiliation":[{"name":"Displays and Photonic Applications Group (GDAF-UC3M), Electronic Technology Department, Carlos III University of Madrid, Av de la Universidad 30, E28911 Legan\u00e9s, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4979-9098","authenticated-orcid":false,"given":"Isabel","family":"P\u00e9rez","sequence":"additional","affiliation":[{"name":"Displays and Photonic Applications Group (GDAF-UC3M), Electronic Technology Department, Carlos III University of Madrid, Av de la Universidad 30, E28911 Legan\u00e9s, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Virginia","family":"Urruchi","sequence":"additional","affiliation":[{"name":"Displays and Photonic Applications Group (GDAF-UC3M), Electronic Technology Department, Carlos III University of Madrid, Av de la Universidad 30, E28911 Legan\u00e9s, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5903-5967","authenticated-orcid":false,"given":"Jos\u00e9 Manuel","family":"S\u00e1nchez-Pena","sequence":"additional","affiliation":[{"name":"Displays and Photonic Applications Group (GDAF-UC3M), Electronic Technology Department, Carlos III University of Madrid, Av de la Universidad 30, E28911 Legan\u00e9s, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,10,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Lemmer, A., and Ullrich, T. (2018). Effect of different operating temperatures on the biological hydrogen methanation in trickle bed reactors. Energies, 11.","DOI":"10.3390\/en11061344"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Wang, Y., Li, P., Truong-Dinh Tran, T., Zhang, J., and Kong, L. (2016). Manufacturing techniques and surface Engineering of polymer based nanoparticles for targeted drug delivery to cancer. Nanomaterials, 6.","DOI":"10.3390\/nano6020026"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Kotsuchibashi, Y., Ebara, M., Aoyagi, T., and Narain, R. (2016). Recent advances in dual temperature Responsive Block copolymers and their potential as biomedical applications. Polymers, 8.","DOI":"10.3390\/polym8110380"},{"key":"ref_4","unstructured":"Pollock, D.D. (1991). Thermocouples: Theory and Properties, CRC Press."},{"key":"ref_5","unstructured":"Kalsi, H.S. (2010). Electronic Instrumentation, McGraw-Hill Education. [3rd ed.]."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"13076","DOI":"10.3390\/s131013076","article-title":"A temperature sensor based on a polymer optical fiber macro-bend","volume":"13","author":"Moraleda","year":"2013","journal-title":"Sensors"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"De Gennes, P.G. (1975). The Physics of Liquid Crystal, Oxford University Press.","DOI":"10.1063\/1.3069010"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Blinov, L.M., and Chigrinov, V.G. (1994). Electrooptic Effects in Liquid Crystal Materials, Springer.","DOI":"10.1007\/978-1-4612-2692-5"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2002","DOI":"10.1364\/OPEX.12.002002","article-title":"High temperature-gradient refractive index liquid crystals","volume":"12","author":"Li","year":"2004","journal-title":"Opt. Express"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Yang, D.-K., and Wu, S.-T. (2014). Liquid Crystal Materials. Fundamentals of Liquid Crystal Devices, John Wiley and Sons, Ltd.. [2nd ed.].","DOI":"10.1002\/9781118751992"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"5594","DOI":"10.3390\/s150305594","article-title":"Temperature-phase converter based on a LC cell as a variable capacitance","volume":"15","author":"Torres","year":"2015","journal-title":"Sensors"},{"key":"ref_12","first-page":"1","article-title":"Liquid crystals for electro-optic applications","volume":"Volume 7","author":"Nalwa","year":"2001","journal-title":"Handbook of Advanced Electronic and Photonic Materials and Devices, Ten-Volume Set"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Yasuura, H., Kyung, C.-M., Liu, Y., and Lin, Y.-L. (2018). Smart Sensors at the IoT Frontier, Springer.","DOI":"10.1007\/978-3-319-55345-0"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1021\/acssensors.7b00047","article-title":"Wearable, Flexible, and Multifunctional Healthcare Device with an ISFET Chemical Sensor for Simultaneous Sweat pH and Skin Temperature Monitoring","volume":"2","author":"Nakata","year":"2017","journal-title":"ACS Sens."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"7982","DOI":"10.3390\/s8127982","article-title":"A Passive Wireless Temperature sensor for harsh environment applications","volume":"8","author":"Wang","year":"2008","journal-title":"Sensors"},{"key":"ref_16","first-page":"325","article-title":"A wireless inductive-capacitive (L-C) sensor for rotating component temperature monitoring","volume":"4","author":"Rodriguez","year":"2011","journal-title":"Int. J. Smart Sens. Intell. Syst."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Birdsell, E.D., Park, J., and Allen, M.G. (2004, January 11\u201314). Wireless ceramic sensors operating in high temperature environments. Proceedings of the 40th AIAA\/ASME\/SAE\/ASEE Joint Propulsion Conference and Exhibit, Fort Lauderdale, FL, USA.","DOI":"10.2514\/6.2004-3990"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1109\/84.982864","article-title":"Passive humidity monitoring system for in situ remote wireless testing of micropackages","volume":"11","author":"Harpster","year":"2002","journal-title":"J. Microelectromech. Syst."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Yan, D., Yang, Y., Hong, Y., Liang, T., Yao, Z., Chen, X., and Xiong, J. (2018). Low-cost wireless temperature measurement: design, manufacture, and testing of a PCB-based wireless passive temperature sensor. Sensors, 18.","DOI":"10.3390\/s18020532"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Woodard, S.E., Taylor, B.D., Shams, Q.A., and Fox, R.L. (2003, January 17\u201319). L-C Measurement Acquisition Method for Aerospace Systems. Proceedings of the 2003 AIAA Aviation Technology, Integration and Operations Technical Forum, Denver, CO, USA. Paper No. 2003-6842.","DOI":"10.2514\/6.2003-6842"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1109\/JDT.2012.2222015","article-title":"Figure of Merit of Polymer-Stabilized Blue Phase Liquid Crystals","volume":"9","author":"Yan","year":"2013","journal-title":"J. Disp. Technol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2118","DOI":"10.1016\/j.physb.2010.01.116","article-title":"Homeotropic alignment of nematic liquid crystals with negative dielectric anisotropy","volume":"405","author":"Singh","year":"2010","journal-title":"Phys. B Condens. Matter"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3483","DOI":"10.1063\/1.1388163","article-title":"Ionic contribution to the dielectric properties of a nematic liquid crystal in thin cells","volume":"90","author":"Dhara","year":"2001","journal-title":"J. Appl. Phys."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"204","DOI":"10.1109\/TDEI.2006.1593418","article-title":"Electrical modeling of liquid crystal displays-LCDs","volume":"13","author":"Costa","year":"2006","journal-title":"IEEE Trans. Dielectr. Electr. 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