{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,23]],"date-time":"2025-12-23T10:02:50Z","timestamp":1766484170145,"version":"build-2065373602"},"reference-count":61,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2020,10,23]],"date-time":"2020-10-23T00:00:00Z","timestamp":1603411200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001659","name":"Deutsche Forschungsgemeinschaft","doi-asserted-by":"publisher","award":["MO 1060\/29-1 and FR 1301\/23-1"],"award-info":[{"award-number":["MO 1060\/29-1 and FR 1301\/23-1"]}],"id":[{"id":"10.13039\/501100001659","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Recently, a laboratory setup for microwave-based characterization of powder samples at elevated temperatures and different gas atmospheres was presented. The setup is particularly interesting for operando investigations on typical materials for exhaust gas aftertreatment. By using the microwave cavity perturbation method, where the powder is placed inside a cavity resonator, the change of the resonant properties provides information about changes in the dielectric properties of the sample. However, determining the exact complex permittivity of the powder samples is not simple. Up to now, a simplified microwave cavity perturbation theory had been applied to estimate the bulk properties of the powders. In this study, an extended approach is presented which allows to determine the dielectric properties of the powder materials more correctly. It accounts for the electric field distribution in the resonator, the depolarization of the sample and the effect of the powder filling. The individual method combines findings from simulations and recognized analytical approaches and can be used for investigations on a wide range of materials and sample geometries. This work provides a more accurate evaluation of the dielectric powder properties and has the potential to enhance the understanding of the microwave behavior of storage materials for exhaust gas aftertreatment, especially with regard to the application of microwave-based catalyst state diagnosis.<\/jats:p>","DOI":"10.3390\/s20216024","type":"journal-article","created":{"date-parts":[[2020,10,23]],"date-time":"2020-10-23T08:59:28Z","timestamp":1603443568000},"page":"6024","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Determination of the Dielectric Properties of Storage Materials for Exhaust Gas Aftertreatment Using the Microwave Cavity Perturbation Method"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1410-6979","authenticated-orcid":false,"given":"Carsten","family":"Steiner","sequence":"first","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Department of Functional Materials, University of Bayreuth, 95440 Bayreuth, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8529-4121","authenticated-orcid":false,"given":"Stefanie","family":"Walter","sequence":"additional","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Department of Functional Materials, University of Bayreuth, 95440 Bayreuth, Germany"}]},{"given":"Vladimir","family":"Malashchuk","sequence":"additional","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Department of Functional Materials, University of Bayreuth, 95440 Bayreuth, Germany"}]},{"given":"Gunter","family":"Hagen","sequence":"additional","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Department of Functional Materials, University of Bayreuth, 95440 Bayreuth, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6855-8460","authenticated-orcid":false,"given":"Iurii","family":"Kogut","sequence":"additional","affiliation":[{"name":"Institute of Energy Research and Physical Technologies, Clausthal University of Technology, 38640 Goslar, Germany"}]},{"given":"Holger","family":"Fritze","sequence":"additional","affiliation":[{"name":"Institute of Energy Research and Physical Technologies, Clausthal University of Technology, 38640 Goslar, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7622-0120","authenticated-orcid":false,"given":"Ralf","family":"Moos","sequence":"additional","affiliation":[{"name":"Bayreuth Engine Research Center (BERC), Department of Functional Materials, University of Bayreuth, 95440 Bayreuth, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2020,10,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2035","DOI":"10.1007\/s11244-009-9399-6","article-title":"Direct Catalyst Monitoring by Electrical Means: An Overview on Promising Novel Principles","volume":"52","author":"Moos","year":"2009","journal-title":"Top. 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