{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,6]],"date-time":"2026-05-06T16:11:21Z","timestamp":1778083881659,"version":"3.51.4"},"reference-count":29,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2022,11,5]],"date-time":"2022-11-05T00:00:00Z","timestamp":1667606400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["62222401"],"award-info":[{"award-number":["62222401"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61874038"],"award-info":[{"award-number":["61874038"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["LXR22F040001"],"award-info":[{"award-number":["LXR22F040001"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["LD22F040001"],"award-info":[{"award-number":["LD22F040001"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["62222401"],"award-info":[{"award-number":["62222401"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61874038"],"award-info":[{"award-number":["61874038"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["LXR22F040001"],"award-info":[{"award-number":["LXR22F040001"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["LD22F040001"],"award-info":[{"award-number":["LD22F040001"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Zhejiang Provincial Natural Science Foundation","doi-asserted-by":"publisher","award":["62222401"],"award-info":[{"award-number":["62222401"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Zhejiang Provincial Natural Science Foundation","doi-asserted-by":"publisher","award":["61874038"],"award-info":[{"award-number":["61874038"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Zhejiang Provincial Natural Science Foundation","doi-asserted-by":"publisher","award":["LXR22F040001"],"award-info":[{"award-number":["LXR22F040001"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Zhejiang Provincial Natural Science Foundation","doi-asserted-by":"publisher","award":["LD22F040001"],"award-info":[{"award-number":["LD22F040001"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Zhejiang Provincial Natural Science Foundation","doi-asserted-by":"publisher","award":["62222401"],"award-info":[{"award-number":["62222401"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Zhejiang Provincial Natural Science Foundation","doi-asserted-by":"publisher","award":["61874038"],"award-info":[{"award-number":["61874038"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Zhejiang Provincial Natural Science Foundation","doi-asserted-by":"publisher","award":["LXR22F040001"],"award-info":[{"award-number":["LXR22F040001"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Zhejiang Provincial Natural Science Foundation","doi-asserted-by":"publisher","award":["LD22F040001"],"award-info":[{"award-number":["LD22F040001"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This study proposes an ultrahigh-sensitivity split-ring resonator-based microwave sensor for retrieving the complex permittivity of liquid samples. An interdigital capacitor structure was used to expand the sensing area and the sensitivity. A defected ground structure and A parallel dual split-ring resonator were introduced to improve the quality factor. A polydimethylsiloxane microfluidic channel substrate was placed above the interdigital capacitor structure. The channel route coincided with the interdigital gap to fully utilize the strong electric field. Ethanol\u2013water solutions with varying ethanol fractions were injected into the channel as the testing liquid. It was demonstrated that the variation in resonant frequency can be used to retrieve the dielectric properties of liquid samples. The proposed sensor used a small liquid volume of ~0.68 \u03bcL and provided values in good agreement with the reference data.<\/jats:p>","DOI":"10.3390\/s22218534","type":"journal-article","created":{"date-parts":[[2022,11,7]],"date-time":"2022-11-07T03:02:22Z","timestamp":1667790142000},"page":"8534","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":37,"title":["An Improved Split-Ring Resonator-Based Sensor for Microfluidic Applications"],"prefix":"10.3390","volume":"22","author":[{"given":"Wei","family":"Ye","sequence":"first","affiliation":[{"name":"MOE Engineering Research Center of Smart Micro-Sensors and Micro-Systems, School of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China"}]},{"given":"Da-Wei","family":"Wang","sequence":"additional","affiliation":[{"name":"MOE Engineering Research Center of Smart Micro-Sensors and Micro-Systems, School of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China"}]},{"given":"Jing","family":"Wang","sequence":"additional","affiliation":[{"name":"MOE Engineering Research Center of Smart Micro-Sensors and Micro-Systems, School of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8599-7249","authenticated-orcid":false,"given":"Gaofeng","family":"Wang","sequence":"additional","affiliation":[{"name":"MOE Engineering Research Center of Smart Micro-Sensors and Micro-Systems, School of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2507-5776","authenticated-orcid":false,"given":"Wen-Sheng","family":"Zhao","sequence":"additional","affiliation":[{"name":"MOE Engineering Research Center of Smart Micro-Sensors and Micro-Systems, School of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"9503414","DOI":"10.1109\/TIM.2020.3040484","article-title":"Resonator-based microwave metamaterial sensors for instrumentation: Survey, classification, and performance comparison","volume":"70","author":"Mayani","year":"2021","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"113311","DOI":"10.1016\/j.sna.2021.113311","article-title":"Design of H-shaped planar displacement microwave sensors with wide dynamic range","volume":"333","author":"Zhu","year":"2021","journal-title":"Sens. Actuators A Phys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1876","DOI":"10.1109\/TAP.2019.2938609","article-title":"Differential sensor based on electroinductive wave transmission lines for dielectric constant measurements and defect detection","volume":"68","author":"Gil","year":"2020","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1109\/TMTT.2015.2503275","article-title":"Ultrahigh-Sensitivity mediator-free biosensor based on a microfabricated microwave resonator for the detection of micromolar glucose concentrations","volume":"64","author":"Adhikari","year":"2016","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"4269","DOI":"10.1109\/TMTT.2019.2932737","article-title":"Ultrahigh-sensitivity microwave sensor for microfluidic complex permittivity measurement","volume":"67","author":"Ebrahimi","year":"2019","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"18756","DOI":"10.1109\/JSEN.2021.3090086","article-title":"Ultrahigh-sensitivity microwave microfluidic sensors based on modified complementary electric-LC and split-ring resonator structures","volume":"21","author":"Wu","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"17859","DOI":"10.1109\/JSEN.2021.3085954","article-title":"Dielectric characterization of liquid mixtures using EIT-like transmission window","volume":"21","author":"Xu","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1201","DOI":"10.1109\/LMWC.2020.3029060","article-title":"An ultrahigh sensitivity microwave sensor for microfluidic applications","volume":"30","author":"Fan","year":"2020","journal-title":"IEEE Microw. Wirel. Compon. Lett."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"576","DOI":"10.1109\/TMTT.2021.3109599","article-title":"High-resolution, sensitivity-enhanced active resonator sensor using substrate-embedded channel for characterizing low-concentration liquid mixtures","volume":"70","author":"Mohammadi","year":"2022","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"5876","DOI":"10.1109\/JSEN.2020.2973196","article-title":"Differential microwave microfluidic sensor based on microstrip complementary split-ring resonator (MCSRR) structure","volume":"20","author":"Gan","year":"2020","journal-title":"IEEE Sens. J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"8004710","DOI":"10.1109\/TIM.2021.3113135","article-title":"Highly sensitive ELC resonator based differential sensor","volume":"70","author":"Varshney","year":"2021","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"486","DOI":"10.1109\/LMWC.2010.2051218","article-title":"A novel time domain method to extract equivalent circuit model of patterned ground structures","volume":"20","author":"Cheng","year":"2010","journal-title":"IEEE Microw. Wirel. Compon. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"12189","DOI":"10.1109\/JSEN.2021.3062290","article-title":"Single-frequency amplitude-modulation sensor for dielectric characterization of solids and microfluidics","volume":"21","author":"Ebrahimi","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"20010","DOI":"10.1109\/JSEN.2021.3099298","article-title":"High sensitivity sensor loaded with octagonal spiral resonators for retrieval of solid material permittivity","volume":"32","author":"Liu","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.sna.2012.10.027","article-title":"Metamaterial-based microfluidic sensor for dielectric characterization","volume":"189","author":"Withayachumnankul","year":"2012","journal-title":"Sens. Actuators A Phys."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1345","DOI":"10.1109\/JSEN.2013.2295312","article-title":"High-sensitivity metamaterial-inspired sensor for microfluidic dielectric characterization","volume":"14","author":"Ebrahimi","year":"2014","journal-title":"IEEE Sens. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"24075","DOI":"10.1109\/JSEN.2021.3115570","article-title":"A temperature-compensated differential microstrip sensor for microfluidic applications","volume":"21","author":"Wu","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1017","DOI":"10.1109\/TBCAS.2021.3112744","article-title":"Sensitivity-enhanced fluidic glucose sensor based on a microwave resonator coupled with an interferometric system for noninvasive and continuous detection","volume":"15","author":"Jang","year":"2022","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Shaw, T., and Mitra, D. (2017, January 11\u201313). Electromagnetic metamaterial based sensor design for chemical discrimination. Proceedings of the 2017 IEEE MTT-S International Microwave and RF Conference (IMaRC), Ahmedabad, India.","DOI":"10.1109\/IMaRC.2017.8611244"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"6589","DOI":"10.1109\/JSEN.2017.2747764","article-title":"Microwave microfluidic sensor based on a microstrip splitter\/combiner configuration and split ring resonators (SRRs) for dielectric characterization of liquids","volume":"17","author":"Su","year":"2017","journal-title":"IEEE Sens. J."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Bahar, A.A.M., Zakaria, Z., Isa, A.A.M., Alahnomi, R.A., and Rahman, N.A. (2018, January 19\u201322). Complex permittivity measurement based on planar microfluidic resonator sensor. Proceedings of the 18th International Symposium Antenna Technology and Applied Electromagnetics (ANTEM), Waterloo, ON, Canada.","DOI":"10.1109\/ANTEM.2018.8572934"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2080","DOI":"10.1109\/TMTT.2020.2978051","article-title":"Integration of interdigitated electrodes in split-ring resonator for detecting liquid mixtures","volume":"68","author":"Bao","year":"2020","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Ma, J., Tang, J., Wang, K., Guo, L., Gong, Y., and Wang, S. (2021). Complex permittivity characterization of liquid samples based on a split ring resonator (SRR). Sensors, 21.","DOI":"10.3390\/s21103385"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1451","DOI":"10.1109\/TMTT.2005.845211","article-title":"Equivalent-circuit models for split-ring resonators and complementary split-ring resonators coupled to planar transmission lines","volume":"53","author":"Baena","year":"2005","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"9138","DOI":"10.1109\/JSEN.2021.3053938","article-title":"Three-dimensional split-ring resonators-based sensors for fluid detection","volume":"21","author":"Albishi","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"11900","DOI":"10.1109\/JSEN.2019.2938853","article-title":"Metamaterial-Inspired microwave microfluidic sensor for glucose monitoring in aqueous solutions","volume":"19","author":"Govind","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Karmakar, N.C., Roy, S.M., Balbin, I., and Swiegers, G.F. (2005, January 21\u201324). Quasi-Static analysis of defected ground structure. Proceedings of the TENCON 2005-2005 IEEE Region 10 Conference, Melbourne, VIC, Australia.","DOI":"10.1109\/TENCON.2005.300904"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"4441","DOI":"10.1063\/1.471197","article-title":"Microwave dielectric characterization of binary mixtures of water, methanol, and ethanol","volume":"104","author":"Bao","year":"1996","journal-title":"J. Chem. Phys."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1843","DOI":"10.1109\/TMTT.2018.2791942","article-title":"Strongly enhanced sensitivity in planar microwave sensors based on metamaterial coupling","volume":"66","author":"Abdolrazzaghi","year":"2018","journal-title":"IEEE Trans. Microw. Theory Tech."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/21\/8534\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:11:21Z","timestamp":1760145081000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/21\/8534"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,11,5]]},"references-count":29,"journal-issue":{"issue":"21","published-online":{"date-parts":[[2022,11]]}},"alternative-id":["s22218534"],"URL":"https:\/\/doi.org\/10.3390\/s22218534","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,11,5]]}}}