{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,27]],"date-time":"2026-06-27T12:58:29Z","timestamp":1782565109669,"version":"3.54.5"},"reference-count":35,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2020,9,29]],"date-time":"2020-09-29T00:00:00Z","timestamp":1601337600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005230","name":"Natural Science Foundation of Chongqing","doi-asserted-by":"publisher","award":["cstc2018jcyjAX0508"],"award-info":[{"award-number":["cstc2018jcyjAX0508"]}],"id":[{"id":"10.13039\/501100005230","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Research Program of Chongqing Municipal Education Commission","award":["KJQN201800639"],"award-info":[{"award-number":["KJQN201800639"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In order to improve the sensitivity of liquid dielectric constant measurements, a liquid dielectric constant sensor based on a cubic container structure is proposed for the first time. The cubic container, which consists of a dielectric substrate with a split resonant ring (SRR) and microstrip lines, can enhance the electric field intensity in the measuring area. High sensitivity can be obtained from measuring the dielectric constant with the characteristics of the structure resonate. The research results show that the resonant frequency of the sensor is shifted from 7.69 GHz to 5.70 GHz, with about a 2 GHz frequency offset, when the dielectric constant of the sample varied from 1 to 10. A resonance frequency offset of 200 MHz for the per unit dielectric constant is achieved, which is excellent regarding performance. The permittivity of oil with a different metal content is measured by using the relation between the fitted permittivity and the resonant frequency. The relative error is less than 1.5% and the sensitivity of measuring is up to 3.45%.<\/jats:p>","DOI":"10.3390\/s20195598","type":"journal-article","created":{"date-parts":[[2020,9,29]],"date-time":"2020-09-29T20:56:22Z","timestamp":1601412982000},"page":"5598","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":38,"title":["Design of a High Sensitivity Microwave Sensor for Liquid Dielectric Constant Measurement"],"prefix":"10.3390","volume":"20","author":[{"given":"Honggang","family":"Hao","sequence":"first","affiliation":[{"name":"College of Electronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dexu","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Electronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhu","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Electronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Yin","sequence":"additional","affiliation":[{"name":"College of Electronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei","family":"Ruan","sequence":"additional","affiliation":[{"name":"College of Electronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,9,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2766","DOI":"10.1109\/JSEN.2017.2682266","article-title":"High-Q Sensor Based on Symmetrical Split Ring Resonator with Spurlines for Solids Material Detection","volume":"17","author":"Alahnomi","year":"2017","journal-title":"IEEE Sens. J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"48324","DOI":"10.1109\/ACCESS.2018.2867077","article-title":"Highly-Sensitive Microwave Sensors based on Open Complementary Split Ring Resonators (OCSRRs) for Dielectric Characterization and Solute Concentration Measurement in Liquids","volume":"6","author":"Velez","year":"2018","journal-title":"IEEE Access"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Liu, W., Sun, H., and Xu, L. (2018). A Microwave Method for Dielectric Characterization Measurement of Small Liquids Using a Metamaterial-Based Sensor. Sensors, 18.","DOI":"10.3390\/s18051438"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Wei, Z., Huang, J., Li, J., Xu, G., Ju, Z., Liu, X., and Ni, X. (2018). A High-Sensitivity Microfluidic Sensor Based on a Substrate Integrated Waveguide Re-Entrant Cavity for Complex Permittivity Measurement of Liquids. Sensors, 18.","DOI":"10.3390\/s18114005"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2428","DOI":"10.1109\/TMTT.2020.2979964","article-title":"Permittivity Determination Considering the Metal Surface Roughness Effect on the Microstrip Line Series Inductance and Shunt Capacitance","volume":"68","year":"2020","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_6","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_7","doi-asserted-by":"crossref","first-page":"972","DOI":"10.1109\/TMTT.2012.2231877","article-title":"A Microwave and Microfluidic Planar Resonator for Efficient and Accurate Complex Permittivity Characterization of Aqueous Solutions","volume":"61","author":"Chretiennot","year":"2012","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Naqui, J., Damm, C., Wiens, A., Jakoby, R., Su, L., and Mart\u00edn, F. (2014, January 1\u20136). Transmission lines loaded with pairs of magnetically coupled stepped impedance resonators (SIRs): Modeling and application to microwave sensors. Proceedings of the IEEE MTT-S International Microwave Symposium, Tampa, FL, USA.","DOI":"10.1109\/MWSYM.2014.6848494"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/j.aeue.2018.02.026","article-title":"A compact dual, triple band resonators for negative permittivity metamaterial","volume":"88","author":"Marathe","year":"2018","journal-title":"AEU Int. J. Electron. Commun."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Vanchenko, I., Khruslov, M., Popenko, N., Plakhtii, V., and Tkach, V. (2020). Modified cavity perturbation method for high recision measurements of complex permittivity throughout the \u0425-band. Microw. Opt. Technol. Lett.","DOI":"10.1002\/mop.32456"},{"key":"ref_11","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":"2013","journal-title":"IEEE Sens. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"64704","DOI":"10.1063\/1.3442512","article-title":"Complex permittivity measurements using cavity perturbation technique with substrate integrated waveguide cavities","volume":"81","author":"Murthy","year":"2010","journal-title":"Rev. Sci. Instrum."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"7181","DOI":"10.1109\/JSEN.2015.2469683","article-title":"Design and Application of the CSRR-Based Planar Sensor for Noninvasive Measurement of Complex Permittivity","volume":"15","author":"Ansari","year":"2015","journal-title":"IEEE Sens. J."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1109\/LMWC.2014.2318900","article-title":"Complementary Split-Ring Resonators for Measuring Dielectric Constants and Loss Tangents","volume":"24","author":"Lee","year":"2014","journal-title":"IEEE Microw. Wirel. Components Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1109\/TMTT.2015.2503764","article-title":"Noncontact Measurement of Complex Permittivity and Thickness by Using Planar Resonators","volume":"64","author":"Yang","year":"2015","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Su, L., Mata-Contreras, J., V\u00e9lez, P., Fern\u00e1ndez-Prieto, A., and Mart\u00edn, F. (2018). Analytical Method to Estimate the Complex Permittivity of Oil Samples. Sensors, 18.","DOI":"10.3390\/s18040984"},{"key":"ref_17","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 (SRR) for dielectric characterization of liquids","volume":"17","author":"Su","year":"2017","journal-title":"IEEE Sens. J."},{"key":"ref_18","unstructured":"Reyes, V.E., Acevedo-Osorio, G., Arias-Correa, M., and Senior, D.E. (2019). A Submersible Printed Sensor Based on a c for Permittivity Characterization. Sensors, 19."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3587","DOI":"10.1109\/JSEN.2016.2538086","article-title":"Submersible Printed Split-Ring Resonator-Based Sensor for Thin-Film Detection and Permittivity Characterization","volume":"16","author":"Gil","year":"2016","journal-title":"IEEE Sens. J."},{"key":"ref_20","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."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"386","DOI":"10.1016\/j.sna.2018.06.008","article-title":"Reconfigurable microwave SIW sensor based on PBG structure for high accuracy permittivity characterization of industrial liquids","volume":"283","author":"Jafari","year":"2018","journal-title":"Sens. Actuators A Phys."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Salim, A., and Lim, S. (2016). Complementary Split-Ring Resonator-Loaded Microfluidic Ethanol Chemical Sensor. Sensors, 16.","DOI":"10.3390\/s16111802"},{"key":"ref_23","unstructured":"Abhishek, K., Jha, M., and Jaleel, A. (2014, January 16\u201319). SIW cavity-based RF sensor for dielectric characterization of liquids. Proceedings of the IEEE Conference on Antenna Measurements & Applications (CAMA), Antibes Juan-les-Pins, France."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2160","DOI":"10.1109\/TMTT.2014.2333711","article-title":"Wireless Sensing of Complex Dielectric Permittivity of Liquids Based on the RFID","volume":"62","year":"2014","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Hao, H., Wang, D., and Wang, Z. (2020). Design of Substrate-Integrated Waveguide Loading Multiple Complementary Open Resonant Rings (CSRRs) for Dielectric Constant Measurement. Sensors, 20.","DOI":"10.3390\/s20030857"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Mart\u00edn, F., V\u00e9lez, P., and Gil, M. (2020). Microwave Sensors Based on Resonant Elements. Sensors, 20.","DOI":"10.3390\/s20123375"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"939","DOI":"10.1109\/LMWC.2018.2860596","article-title":"A Dual-Mode Split-Ring Resonator to Eliminate Relative Humidity Impact","volume":"28","author":"Abdolrazzaghi","year":"2018","journal-title":"IEEE Microw. Wirel. Componen. Lett."},{"key":"ref_28","first-page":"2562","article-title":"Split Ring Resonator-Based Microwave Fluidic Sensors for Electrolyte Concentration Measurements","volume":"19","author":"Grenier","year":"2018","journal-title":"IEEE Sens. J."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"4362","DOI":"10.1109\/TMTT.2016.2623311","article-title":"Splitter\/Combiner Microstrip Sections Loaded with Pairs of Complementary Split Ring Resonators (CSRRs): Modeling and Optimization for Differential Sensing Applications","volume":"64","author":"Su","year":"2016","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_30","unstructured":"Abdolrazzaghi, M., Zarifi, M.H., and Daneshmand, M. (November, January Octtober). Sensitivity enhancement of split ring resonator based liquid sensors. Proceedings of the IEEE SENSORS, Orlando, FL, USA."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"083705","DOI":"10.1063\/1.4893751","article-title":"Dual-mode behavior of the complementary electric-LC resonators loaded on transmission line: Analysis and applications","volume":"116","author":"Ebrahimi","year":"2014","journal-title":"J. Appl. Phys."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Hong, J., and Lancaster, M. (2001). Microstrip Filters for RF\/Microwave Applications, Wiley.","DOI":"10.1002\/0471221619"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1511","DOI":"10.1109\/TMTT.2016.2645156","article-title":"Resonance Characteristics of Substrate-Integrated Rectangular Cavity and Their Applications to Dual-Band and Wide-Stopband Bandpass Filters Design","volume":"65","author":"Zhou","year":"2017","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_34","first-page":"94","article-title":"Oil Monitoring Method Based on the Dielectric Constant","volume":"34","author":"Liu","year":"2009","journal-title":"Lubr. Eng."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1863","DOI":"10.1109\/TMTT.2011.2132141","article-title":"Permittivity Measurements at Microwave Frequencies Using Epsilon-Near-Zero (ENZ) Tunnel Structure","volume":"59","author":"Murthy","year":"2011","journal-title":"IEEE Trans. Microw. Theory Tech."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/19\/5598\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:14:59Z","timestamp":1760177699000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/19\/5598"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,9,29]]},"references-count":35,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2020,10]]}},"alternative-id":["s20195598"],"URL":"https:\/\/doi.org\/10.3390\/s20195598","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,9,29]]}}}