{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T15:07:56Z","timestamp":1781622476695,"version":"3.54.5"},"reference-count":25,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2016,1,25]],"date-time":"2016-01-25T00:00:00Z","timestamp":1453680000000},"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>In this paper, multi-channel capacitive sensor arrays based on microstrip band-stop filters are studied. The sensor arrays can be used to detect the proximity of objects at different positions and directions. Each capacitive sensing structure in the array is connected to an inductive element to form resonance at different frequencies. The resonances are designed to be isolated in the frequency spectrum, such that the change in one channel does not affect resonances at other channels. The inductive element associated with each capacitive sensor can be surface-mounted inductors, integrated microstrip inductors or metamaterial-inspired structures. We show that by using metamaterial split-ring structures coupled to a microstrip line, the quality factor of each resonance can be greatly improved compared to conventional surface-mounted or microstrip meander inductors. With such a microstrip-coupled split-ring design, more sensing elements can be integrated in the same frequency spectrum, and the sensitivity can be greatly improved.<\/jats:p>","DOI":"10.3390\/s16020150","type":"journal-article","created":{"date-parts":[[2016,1,25]],"date-time":"2016-01-25T10:03:06Z","timestamp":1453716186000},"page":"150","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Multi-Channel Capacitive Sensor Arrays"],"prefix":"10.3390","volume":"16","author":[{"given":"Bingnan","family":"Wang","sequence":"first","affiliation":[{"name":"Mitsubishi Electric Research Laboratories, 201 Broadway, Cambridge, MA 02139, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiang","family":"Long","sequence":"additional","affiliation":[{"name":"Mitsubishi Electric Research Laboratories, 201 Broadway, Cambridge, MA 02139, USA"},{"name":"University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Koon","family":"Teo","sequence":"additional","affiliation":[{"name":"Mitsubishi Electric Research Laboratories, 201 Broadway, Cambridge, MA 02139, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2016,1,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"469","DOI":"10.1109\/4.753679","article-title":"A 600-dpi capacitive fingerprint sensor chip and image-synthesis technique","volume":"34","author":"Lee","year":"1999","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_2","first-page":"1625","article-title":"A textile based capacitive pressure sensor","volume":"2","author":"Sergio","year":"2002","journal-title":"Sensors"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1833","DOI":"10.1109\/TIM.2006.881558","article-title":"An online flow pattern identification system for gas\u2013oil two-phase flow using electrical capacitance tomography","volume":"55","author":"Xie","year":"2006","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"783","DOI":"10.1088\/0967-3334\/29\/7\/007","article-title":"A multichannel portable ecg system with capacitive sensors","volume":"29","author":"Oehler","year":"2008","journal-title":"Physiol. Meas."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Sato, M., Poupyrev, I., and Harrison, C. (2012, January 5\u201310). Touch\u00e9: Enhancing touch interaction on humans, screens, liquids, and everyday objects. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, Austin, TX, USA.","DOI":"10.1145\/2207676.2207743"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1109\/3516.868916","article-title":"Tactile sensors and other distributed sensors with minimal wiring complexity","volume":"5","author":"Nilsson","year":"2000","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Schussler, M., Puentes, M., Mandel, C., and Jakoby, R. (2010, January 23\u201328). Multi-resonant perturbation method for capacitive sensing with composite right\/left-handed transmission lines. Proceedings of the 2010 IEEE MTT-S International Microwave Symposium Digest (MTT 2010), Anaheim, CA, USA.","DOI":"10.1109\/MWSYM.2010.5515276"},{"key":"ref_8","first-page":"911609","article-title":"A multidirectional capacitive proximity sensor array","volume":"2014","author":"Long","year":"2014","journal-title":"Proc. SPIE"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Naqui, J., Zamora, G., Paredes, F., Bonache, J., and Mart\u00edn, F. (2014, January 12\u201314). Metamaterial transmission lines for wireless communications, sensing and RFID. Proceedings of the 2014 14th Mediterranean Microwave Symposium (MMS 2014), Sao Paulo, Brazil.","DOI":"10.1109\/MMS.2014.7088938"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"620","DOI":"10.1049\/el.2014.0572","article-title":"Two-dimensional displacement and alignment sensor based on reflection coefficients of open microstrip lines loaded with split ring resonators","volume":"50","author":"Horestani","year":"2014","journal-title":"Electron. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"632","DOI":"10.1016\/j.snb.2015.10.061","article-title":"Microwave ring resonator-based non-contact interface sensor for oil sands applications","volume":"224","author":"Zarifi","year":"2016","journal-title":"Sens. Actuators B Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"14358","DOI":"10.1021\/acs.jpcc.5b01066","article-title":"Time-Resolved Microwave Photoconductivity (TRMC) Using Planar Microwave Resonators: Application to the Study of Long-Lived Charge Pairs in Photoexcited Titania Nanotube Arrays","volume":"119","author":"Zarifi","year":"2015","journal-title":"J. Phys. Chem. C"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"9628","DOI":"10.3390\/s150509628","article-title":"Angular Displacement and Velocity Sensors Based on Coplanar Waveguides (CPWs) Loaded with S-Shaped Split Ring Resonators (S-SRR)","volume":"15","author":"Naqui","year":"2015","journal-title":"Sensors"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"023509","DOI":"10.1063\/1.4862029","article-title":"A high-Q resonator using biocompatible materials at microwave frequencies","volume":"104","author":"Lee","year":"2014","journal-title":"Appl. Phys. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"689","DOI":"10.1109\/TMTT.2014.2299514","article-title":"Improved split-ring resonator for microfluidic sensing","volume":"62","author":"Rowe","year":"2014","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"224","DOI":"10.1016\/j.sna.2015.06.031","article-title":"High resolution microwave microstrip resonator for sensing applications","volume":"233","author":"Zarifi","year":"2015","journal-title":"Sens. Actuators A Phys."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1912","DOI":"10.1109\/TMTT.2007.904045","article-title":"A tunable bandstop resonator based on a compact slotted ground structure","volume":"55","author":"Wang","year":"2007","journal-title":"IEEE Trans. Microwave Theory Tech."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1109\/LMWC.2010.2097243","article-title":"A tunable microstrip bandpass filter with two independently adjustable transmission zeros","volume":"21","author":"Long","year":"2011","journal-title":"IEEE Microwave Wirel. Compon. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"518","DOI":"10.1109\/TMTT.2011.2178428","article-title":"Miniaturized uwb filters integrated with tunable notch filters using a silicon-based integrated passive device technology","volume":"60","author":"Wu","year":"2012","journal-title":"IEEE Trans. Microwave Theory Tech."},{"key":"ref_20","unstructured":"KeySight Home. Available online: http:\/\/www.keysight.com\/."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"074104","DOI":"10.1063\/1.4913238","article-title":"A metamaterial-inspired sensor for combined inductive-capacitive detection","volume":"106","author":"Long","year":"2015","journal-title":"Appl. Phys. Lett."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Caloz, C., and Itoh, T. (2005). Electromagnetic Metamaterials: Transmission Line Theory and Microwave Applications, John Wiley & Sons.","DOI":"10.1002\/0471754323"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1455","DOI":"10.1109\/JSEN.2011.2173762","article-title":"Metamaterial-inspired multichannel thin-film sensor","volume":"12","author":"Withayachumnankul","year":"2012","journal-title":"Sensors"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Puentes, M., Weiss, C., Schussler, M., and Jakoby, R. (2011, January 8\u20139). Sensor array based on split ring resonators for analysis of organic tissues. Proceedings of the 2011 IEEE MTT-S International Microwave Symposium Digest (MTT 2011), Barcelona, Spain.","DOI":"10.1109\/MWSYM.2011.5972633"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1720","DOI":"10.1109\/TMTT.2012.2189241","article-title":"Frequency multiplexed 2-dimensional sensor array based on split-ring resonators for organic tissue analysis","volume":"60","author":"Puentes","year":"2012","journal-title":"IEEE Trans. Microwave Theory Tech."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/2\/150\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:18:13Z","timestamp":1760210293000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/2\/150"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,1,25]]},"references-count":25,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2016,2]]}},"alternative-id":["s16020150"],"URL":"https:\/\/doi.org\/10.3390\/s16020150","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,1,25]]}}}