{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,31]],"date-time":"2025-12-31T12:20:34Z","timestamp":1767183634856,"version":"build-2065373602"},"reference-count":35,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2023,4,28]],"date-time":"2023-04-28T00:00:00Z","timestamp":1682640000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100007273","name":"Agencia Estatal de Investigacion (Spain)","doi-asserted-by":"publisher","award":["PID2019-107885GB-C31","PDC2022-133091-I00","PDR-2014-2022\/56-30157-021-2A","2021 FISDU 00195","PPR2\/2015\/36"],"award-info":[{"award-number":["PID2019-107885GB-C31","PDC2022-133091-I00","PDR-2014-2022\/56-30157-021-2A","2021 FISDU 00195","PPR2\/2015\/36"]}],"id":[{"id":"10.13039\/501100007273","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Generalitat de Catalunya (Spain)","award":["PID2019-107885GB-C31","PDC2022-133091-I00","PDR-2014-2022\/56-30157-021-2A","2021 FISDU 00195","PPR2\/2015\/36"],"award-info":[{"award-number":["PID2019-107885GB-C31","PDC2022-133091-I00","PDR-2014-2022\/56-30157-021-2A","2021 FISDU 00195","PPR2\/2015\/36"]}]},{"name":"university departments and research units (FI-SDUR)","award":["PID2019-107885GB-C31","PDC2022-133091-I00","PDR-2014-2022\/56-30157-021-2A","2021 FISDU 00195","PPR2\/2015\/36"],"award-info":[{"award-number":["PID2019-107885GB-C31","PDC2022-133091-I00","PDR-2014-2022\/56-30157-021-2A","2021 FISDU 00195","PPR2\/2015\/36"]}]},{"name":"National Center for Scientific and Technological Research (CNRST)","award":["PID2019-107885GB-C31","PDC2022-133091-I00","PDR-2014-2022\/56-30157-021-2A","2021 FISDU 00195","PPR2\/2015\/36"],"award-info":[{"award-number":["PID2019-107885GB-C31","PDC2022-133091-I00","PDR-2014-2022\/56-30157-021-2A","2021 FISDU 00195","PPR2\/2015\/36"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Morphological microwave imaging has shown interesting results on reconstructing biological objects inside the human body, and these parameters represent their actual biological condition, but not their biological activity. In this paper, we propose a novel microwave technique to locate the low-frequency (f\u22431 kHz) -modulated signals produced by a microtag mimicking an action potential and proved it in a cylindrical phantom of the brain region. A set of two combined UWB microwave applicators, operating in the 0.5 to 2.5 GHz frequency band and producing a nsec interrogation pulse, is able to focus its radiated field into a small region of the brain containing the microtag with a modulated photodiode. The illuminating UWB microwave field was first modulated by the low-frequency (f\u22431 kHz) electrical signal produced by the photodiode, inducing modulated microwave currents into the microtag that reradiating back towards the focusing applicators. At the receiving end, the low-frequency (f\u22431 kHz) -modulated signal was first extracted from the full set of the backscattered signals, then focused into the region of interest and spatially represented in the corresponding region of the brain, resulting in a spatial resolution of the images in the order of 10 mm.<\/jats:p>","DOI":"10.3390\/s23094374","type":"journal-article","created":{"date-parts":[[2023,4,28]],"date-time":"2023-04-28T09:54:53Z","timestamp":1682675693000},"page":"4374","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["UWB-Modulated Microwave Imaging for Human Brain Functional Monitoring"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7957-4044","authenticated-orcid":false,"given":"Youness","family":"Akazzim","sequence":"first","affiliation":[{"name":"School of Telecommunication Engineering, Universitat Polit\u00e8cnica de Catalunya, 08034 Barcelona, Spain"},{"name":"System of Information and Telecommunications Laboratory (LaSIT), FS, Abdelmalek Essaadi University, Tetouan 93000, Morocco"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8912-6595","authenticated-orcid":false,"given":"Marc","family":"Jofre","sequence":"additional","affiliation":[{"name":"School of Telecommunication Engineering, Universitat Polit\u00e8cnica de Catalunya, 08034 Barcelona, Spain"},{"name":"Department of Research and Innovation, Hospital General de Granollers, 08402 Granollers, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9722-9140","authenticated-orcid":false,"given":"Otman","family":"El Mrabet","sequence":"additional","affiliation":[{"name":"System of Information and Telecommunications Laboratory (LaSIT), FS, Abdelmalek Essaadi University, Tetouan 93000, Morocco"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0197-5961","authenticated-orcid":false,"given":"Jordi","family":"Romeu","sequence":"additional","affiliation":[{"name":"School of Telecommunication Engineering, Universitat Polit\u00e8cnica de Catalunya, 08034 Barcelona, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0547-901X","authenticated-orcid":false,"given":"Luis","family":"Jofre-Roca","sequence":"additional","affiliation":[{"name":"School of Telecommunication Engineering, Universitat Polit\u00e8cnica de Catalunya, 08034 Barcelona, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2023,4,28]]},"reference":[{"key":"ref_1","unstructured":"Larsen, L.E., and Jacobi, J.H. (1985). Medical Applications of Microwave Imaging, Institute of Electrical and Electronics Engineers Inc.. Technical Report."},{"key":"ref_2","first-page":"76","article-title":"Dielectric properties of normal & malignant human breast tissues at radiowave & microwave frequencies","volume":"21","author":"Chaudhary","year":"1984","journal-title":"Indian J. Biochem. Biophys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1109\/10.52331","article-title":"Medical imaging with a microwave tomographic scanner","volume":"37","author":"Jofre","year":"1990","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Razzicchia, E., Sotiriou, I., Cano-Garcia, H., Kallos, E., Palikaras, G., and Kosmas, P. (2019). Feasibility study of enhancing microwave brain imaging using metamaterials. Sensors, 19.","DOI":"10.3390\/s19245472"},{"key":"ref_5","first-page":"366","article-title":"3D UWB magnitude-combined tomographic imaging for biomedical applications. algorithm validation","volume":"20","year":"2011","journal-title":"Radioengineering"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1155\/2013\/673027","article-title":"Microwave imaging of human forearms: Pilot study and image enhancement","volume":"2013","author":"Gilmore","year":"2013","journal-title":"Int. J. Biomed. Imaging"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Alwan, M., Sadek, S., and Katbay, Z. (2014, January 12\u201314). Investigation of tumor using an antenna scanning system. Proceedings of the 2014 Mediterranean Microwave Symposium (MMS2014), Marrakech, Morocco.","DOI":"10.1109\/MMS.2014.7088995"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Zhang, H., Flynn, B., Erdogan, A.T., and Arslan, T. (2012, January 12\u201313). Microwave imaging for brain tumour detection using an UWB Vivaldi Antenna array. Proceedings of the 2012 Loughborough Antennas & Propagation Conference (LAPC), Loughborough, UK.","DOI":"10.1109\/LAPC.2012.6402964"},{"key":"ref_9","unstructured":"Zhang, H. (2023, March 25). Microwave Imaging for Ultra-Wideband Antenna Based Cancer Detection. Available online: https:\/\/era.ed.ac.uk\/bitstream\/handle\/1842\/9958\/Zhang2015.pdf?sequence=1&isAllowed=y."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2516","DOI":"10.1109\/TBME.2015.2434956","article-title":"Flexible 16 antenna array for microwave breast cancer detection","volume":"62","author":"Bahramiabarghouei","year":"2015","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Zerrad, F.e., Taouzari, M., Makroum, E.M., Aoufi, J.E., Qanadli, S.D., Karaaslan, M., Al-Gburi, A.J.A., and Zakaria, Z. (2023). Microwave Imaging Approach for Breast Cancer Detection Using a Tapered Slot Antenna Loaded with Parasitic Components. Materials, 16.","DOI":"10.3390\/ma16041496"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"378","DOI":"10.1016\/S0014-4827(03)00291-X","article-title":"Stem cells from the adult human brain develop into functional neurons in culture","volume":"289","author":"Westerlund","year":"2003","journal-title":"Exp. Cell Res."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"566","DOI":"10.1134\/S0006350918040206","article-title":"Regulation of Action Potential Frequency and Amplitude by T-type Ca2+ Channel During Spontaneous Synchronous Activity of Hippocampal Neurons","volume":"63","author":"Teplov","year":"2018","journal-title":"Biophysics"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Tovar, K.R., Bridges, D.C., Wu, B., Randall, C., Audouard, M., Jang, J., Hansma, P.K., and Kosik, K.S. (2017). Recording action potential propagation in single axons using multi-electrode arrays. bioRxiv, 126425.","DOI":"10.1101\/126425"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Sharma, M., Gardner, A.T., Strathman, H.J., Warren, D.J., Silver, J., and Walker, R.M. (2018). Acquisition of neural action potentials using rapid multiplexing directly at the electrodes. Micromachines, 9.","DOI":"10.3390\/mi9100477"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"900","DOI":"10.1109\/JSYST.2013.2260620","article-title":"Development of a wearable mobile electrocardiogram monitoring system by using novel dry foam electrodes","volume":"8","author":"Tseng","year":"2013","journal-title":"IEEE Syst. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"47","DOI":"10.2528\/PIERM20092902","article-title":"Contact ECG Recording Using Copper and E-Textile Based Flexible Dry Electrodes","volume":"101","author":"Ren","year":"2021","journal-title":"Prog. Electromagn. Res. M"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"666","DOI":"10.1002\/mop.24110","article-title":"Noncontact heartbeat detection at 2.4, 5.8, and 60 GHz: A comparative study","volume":"51","author":"Obeid","year":"2009","journal-title":"Microw. Opt. Technol. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"El-Samad, S., Obeid, D., Zaharia, G., Sadek, S., and El Zein, G. (2016). Remote heartbeat detection using microwave system from four positions of a normally breathing patient. Int. J. Commun. Antenna Propag., 6.","DOI":"10.15866\/irecap.v6i3.9281"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Obeid, D., Zaharia, G., Sadek, S., and El Zein, G. (2011, January 26\u201329). ECG vs. single-antenna system for heartbeat activity detection. Proceedings of the 4th International Symposium on Applied Sciences in Biomedical and Communication Technologies, Barcelona, Spain.","DOI":"10.1145\/2093698.2093838"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Jiang, X., Geng, Z., Li, X., Peng, L., Kang, B., and Zheng, C. (2017, January 4\u20139). Microwave transmission approach for dynamic dielectric detection at brain functional site. Proceedings of the 2017 IEEE MTT-S International Microwave Symposium (IMS), Honololu, HI, USA.","DOI":"10.1109\/MWSYM.2017.8058828"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"13468","DOI":"10.1109\/ACCESS.2019.2894128","article-title":"Detection of neural activity of brain functional site based on microwave scattering principle","volume":"7","author":"Wang","year":"2019","journal-title":"IEEE Access"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TIM.2022.3165790","article-title":"Superheterodyne microwave system for the detection of bioparticles with coplanar electrodes on a microfluidic platform","volume":"71","author":"Palacios","year":"2022","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Jofre, M., Jofre, L., and Jofre-Roca, L. (2021). On the wireless microwave sensing of bacterial membrane potential in microfluidic-actuated platforms. Sensors, 21.","DOI":"10.20944\/preprints202103.0079.v1"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Gonz\u00e1lez-L\u00f3pez, G., Jofre Roca, L., Amor\u00f3s Garc\u00eda de Valdecasas, S., Rodr\u00edguez-Leor, O., G\u00e1lvez-Mont\u00f3n, C., Bay\u00e9s-Gen\u00eds, A., and O\u2019Callaghan, J. (2019). Resonance-Based microwave technique for body implant sensing. Sensors, 19.","DOI":"10.3390\/s19224828"},{"key":"ref_26","first-page":"284","article-title":"The globus pallidus, deep brain stimulation, and Parkinson\u2019s disease","volume":"8","author":"Dostrovsky","year":"2002","journal-title":"Neuroscientist"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Akazzim, Y., El Mrabet, O., Romeu, J., and Jofre-Roca, L. (2022). Multi-Element UWB Probe Optimization for Medical Microwave Imaging. Sensors, 23.","DOI":"10.3390\/s23010271"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"626","DOI":"10.1109\/LAWP.2019.2899591","article-title":"3-D Printed UWB Microwave Bodyscope for Biomedical Measurements","volume":"18","author":"Rashid","year":"2019","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1140","DOI":"10.1109\/8.596907","article-title":"Antenna characterization in the time domain","volume":"45","author":"Shlivinski","year":"1997","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1555","DOI":"10.1109\/JPROC.2010.2053332","article-title":"Electromagnetic modeling of RFID-modulated scattering mechanism. Application to tag performance evaluation","volume":"98","author":"Bolomey","year":"2010","journal-title":"Proc. IEEE"},{"key":"ref_31","unstructured":"Madanan, G., and Krishna, D.D. (2020). Innovations in Ultra-WideBand Technologies, IntechOpen."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1109\/JPROC.2008.2008854","article-title":"UWB tomographic radar imaging of penetrable and impenetrable objects","volume":"97","author":"Jofre","year":"2009","journal-title":"Proc. IEEE"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2414","DOI":"10.1109\/TIM.2008.926382","article-title":"UWB short-range bifocusing tomographic imaging","volume":"57","author":"Jofre","year":"2008","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"21793","DOI":"10.1038\/s41598-021-01293-4","article-title":"Microwave power penetration enhancement inside an inhomogeneous human head","volume":"11","author":"Rokunuzzaman","year":"2021","journal-title":"Sci. Rep."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"979","DOI":"10.1002\/mop.28229","article-title":"Realistic head phantom to test microwave systems for brain imaging","volume":"56","author":"Mohammed","year":"2014","journal-title":"Microw. Opt. Technol. Lett."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/9\/4374\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:25:54Z","timestamp":1760124354000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/9\/4374"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,4,28]]},"references-count":35,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2023,5]]}},"alternative-id":["s23094374"],"URL":"https:\/\/doi.org\/10.3390\/s23094374","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2023,4,28]]}}}