{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T11:42:10Z","timestamp":1761824530359,"version":"build-2065373602"},"reference-count":16,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2024,2,2]],"date-time":"2024-02-02T00:00:00Z","timestamp":1706832000000},"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":["62204100","2021M691360","ZJ2020101"],"award-info":[{"award-number":["62204100","2021M691360","ZJ2020101"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"publisher","award":["62204100","2021M691360","ZJ2020101"],"award-info":[{"award-number":["62204100","2021M691360","ZJ2020101"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Postdoctoral Research Foundation of Zhejiang Province","award":["62204100","2021M691360","ZJ2020101"],"award-info":[{"award-number":["62204100","2021M691360","ZJ2020101"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Micro direct methanol fuel cells (\u03bcDMFCs) are a promising power source for microelectronic devices and systems. As the operating state and performance of a \u03bcDMFC is generally determined by both electrochemical polarization and methanol crossover, it is important to monitor the methanol concentration in \u03bcDMFCs. Here, we design and fabricate a microwave sensor and integrate it with a \u03bcDMFC for the online detection of methanol concentration in a nonintrusive way. The sensing area is set at the bottom of the anode chamber of a \u03bcDMFC which exhibits a maximum output power density of 28.8 mW cm\u22122 at 30 \u00b0C. With a square ring structure, the dual-mode microwave sensor shows a sensitivity of 9.5 MHz mol\u22121 L. Furthermore, the importance of methanol concentration monitoring is demonstrated in the long term. A relatively smooth methanol decline curve was obtained, which indicated a normal and stable operating status of the \u03bcDMFC. Derived from real-time recording data, fuel utilization was additionally calculated as 28.5%.<\/jats:p>","DOI":"10.3390\/s24030969","type":"journal-article","created":{"date-parts":[[2024,2,2]],"date-time":"2024-02-02T09:42:32Z","timestamp":1706866952000},"page":"969","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Development of a Microwave Sensor for Real-Time Monitoring of a Micro Direct Methanol Fuel Cell"],"prefix":"10.3390","volume":"24","author":[{"given":"Shubin","family":"Zhang","sequence":"first","affiliation":[{"name":"School of Internet of Things Engineering, Jiangnan University, Wuxi 214122, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4811-7094","authenticated-orcid":false,"given":"Tian","family":"Qiang","sequence":"additional","affiliation":[{"name":"School of Internet of Things Engineering, Jiangnan University, Wuxi 214122, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5006-5190","authenticated-orcid":false,"given":"Yanfeng","family":"Jiang","sequence":"additional","affiliation":[{"name":"School of Internet of Things Engineering, Jiangnan University, Wuxi 214122, China"},{"name":"Institute of Advanced Technology, Jiangnan University, Wuxi 214122, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,2,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.energy.2017.03.161","article-title":"Structural design and analysis of a passive DMFC supplied with concentrated methanol solution","volume":"128","author":"Fang","year":"2017","journal-title":"Energy"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.jpowsour.2019.01.088","article-title":"The whole process, bubble dynamic analysis in two-phase transport of the passive miniature direct methanol fuel cells","volume":"416","author":"Yuan","year":"2019","journal-title":"J. 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