{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T17:43:58Z","timestamp":1785433438919,"version":"3.56.0"},"reference-count":47,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T00:00:00Z","timestamp":1782259200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004421","name":"Warsaw University of Technology","doi-asserted-by":"publisher","award":["504\/05049\/1034\/43.052501"],"award-info":[{"award-number":["504\/05049\/1034\/43.052501"]}],"id":[{"id":"10.13039\/501100004421","id-type":"DOI","asserted-by":"publisher"}]},{"award":["504\/05049\/1034\/43.052501"],"award-info":[{"award-number":["504\/05049\/1034\/43.052501"]}],"id":[{"id":"https:\/\/ror.org\/00y0xnp53","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Impulse-based impedance sensing with capacitively coupled electrodes is introduced as a fast, non-contact, and simplified complementary method to conventional capacitive impedance measurements. Unlike frequency-domain methods, the proposed approach derives effective resistive and capacitive properties of a sample from the transient response to a single rectangular pulse. The equivalent circuit model comprises three elements: sample resistance, sample capacitance, and electrode coupling capacitance. From this model, analytical expressions of the transient response were derived, enabling accurate simulation of measured signals and providing the basis for both phantom verification and machine learning training. Importantly, the coupling capacitance, typically considered a limitation in contactless methods, is estimated alongside the sample parameters, providing insight into electrode\u2013object coupling conditions. A machine-learning model trained on simulated circuit responses, including noise and temporal variability, is employed as a low-latency estimator for extracting parameters from measured transient signals. Experimental validation was carried out using a configurable lumped-element equivalent circuit and NaCl solutions of controlled conductivity, cross-verified with conductometric measurements and numerical probe simulations. Across a tested conductivity range, the method achieved estimation errors of 2\u20138%. The proposed approach is intended as a low-latency measurement strategy for simplified capacitively coupled impedance sensing, with potential relevance to future capacitively coupled electrical impedance tomography systems, where rapid acquisition of boundary measurements is prioritized over full frequency-resolved impedance spectroscopy.<\/jats:p>","DOI":"10.3390\/s26133999","type":"journal-article","created":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T03:20:21Z","timestamp":1782357621000},"page":"3999","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Time-Domain Analysis of Rectangular Pulse Response in Capacitive Impedance Sensing Using Capacitively Coupled Contactless Electrodes"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1596-6524","authenticated-orcid":false,"given":"Damian","family":"Wanta","sequence":"first","affiliation":[{"name":"Faculty of Electronics and Information Technology, Warsaw University of Technology, Nowowiejska 15\/19, 00-665 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1524-5049","authenticated-orcid":false,"given":"Waldemar T.","family":"Smolik","sequence":"additional","affiliation":[{"name":"Faculty of Electronics and Information Technology, Warsaw University of Technology, Nowowiejska 15\/19, 00-665 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-8682-2751","authenticated-orcid":false,"given":"Mikhail","family":"Ivanenko","sequence":"additional","affiliation":[{"name":"Faculty of Electronics and Information Technology, Warsaw University of Technology, Nowowiejska 15\/19, 00-665 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0042-0473","authenticated-orcid":false,"given":"Jacek","family":"Kryszyn","sequence":"additional","affiliation":[{"name":"Faculty of Electronics and Information Technology, Warsaw University of Technology, Nowowiejska 15\/19, 00-665 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3442-6152","authenticated-orcid":false,"given":"Oliwia","family":"Makowiecka","sequence":"additional","affiliation":[{"name":"PIT-RADWAR S.A., Poligonowa 30, 04-051 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0204-2322","authenticated-orcid":false,"given":"Grzegorz","family":"Doma\u0144ski","sequence":"additional","affiliation":[{"name":"Faculty of Electronics and Information Technology, Warsaw University of Technology, Nowowiejska 15\/19, 00-665 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6713-9088","authenticated-orcid":false,"given":"Przemys\u0142aw","family":"Wr\u00f3blewski","sequence":"additional","affiliation":[{"name":"Faculty of Electronics and Information Technology, Warsaw University of Technology, Nowowiejska 15\/19, 00-665 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2449-0652","authenticated-orcid":false,"given":"Mateusz","family":"Midura","sequence":"additional","affiliation":[{"name":"Faculty of Electronics and Information Technology, Warsaw University of Technology, Nowowiejska 15\/19, 00-665 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mateusz","family":"Orzechowski","sequence":"additional","affiliation":[{"name":"Faculty of Electronics and Information Technology, Warsaw University of Technology, Nowowiejska 15\/19, 00-665 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"829","DOI":"10.1002\/elps.202400217","article-title":"Contactless Conductivity Detection for Capillary Electrophoresis\u2014Developments From 2020 to 2024","volume":"46","author":"Hauser","year":"2025","journal-title":"Electrophoresis"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"067002","DOI":"10.1088\/2057-1976\/aadff3","article-title":"Drive and measurement electrode patterns for electrode impedance tomography (EIT) imaging of neural activity in peripheral nerve","volume":"4","author":"Hope","year":"2018","journal-title":"Biomed. 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