{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,19]],"date-time":"2026-03-19T20:49:32Z","timestamp":1773953372195,"version":"3.50.1"},"reference-count":47,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2023,3,24]],"date-time":"2023-03-24T00:00:00Z","timestamp":1679616000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Government of Ireland, Disruptive Technology InnovationFund (DTIF)","award":["DT20180031A"],"award-info":[{"award-number":["DT20180031A"]}]},{"name":"University of Birmingham Dynamic Investment Fund","award":["DT20180031A"],"award-info":[{"award-number":["DT20180031A"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Cardiac wireless implantable medical devices (CWIMD) have brought a paradigm shift in monitoring and treating various cardiac conditions, including heart failure, arrhythmias, and hypertension. One of the key elements in CWIMD is the implant antenna which uses radio frequency (RF) technology to wirelessly communicate and transmit data to external devices. However, wireless communication with a deeply implanted antenna using RF can be challenging due to the significant loss of electromagnetic (EM) signal at the air\u2013skin interface, and second, due to the propagation and reflection of EM waves from different tissue boundaries. The air\u2013skin interface loss of the EM wave is pronounced due to the absence of a matching medium. This paper investigates the EM propagation losses in the human body and presents a choice of optimal frequency for the design of the cardiac implant antenna and the dielectric properties of the matching medium. First, the dielectric properties of all tissues present in the human thorax including skin, fat, muscle, cartilage, and heart are analyzed as a function of frequency to study the EM wave absorption at different frequencies. Second, the penetration of EM waves inside the biological tissues is analyzed as a function of frequency. Third, a transmission line (TL) formalism approach is adopted to examine the optimal frequency band for designing a cardiac implant antenna and the matching medium for the air\u2013skin interface. Finally, experimental validation is performed at two ISM frequencies, 433 MHz and 915 MHz, selected from the optimal frequency band (0.4\u20131.5 GHz) suggested by our analytical investigation. For experimental validation, two off-the-shelf flexible dipole antennas operating at selected ISM frequencies were used. The numerical and experimental findings suggested that for the specific application of a cardiac implant with a penetration depth of 7\u201317 cm, the most effective frequency range for operation is within 0.4\u20131.5 GHz. The findings based on the dielectric properties of thorax tissues, the penetration depth of EM waves, and the optimal frequency band have provided valuable information on developing and optimizing CWIMDs for cardiac care applications.<\/jats:p>","DOI":"10.3390\/s23073411","type":"journal-article","created":{"date-parts":[[2023,3,24]],"date-time":"2023-03-24T03:16:46Z","timestamp":1679627806000},"page":"3411","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Optimizing Cardiac Wireless Implant Communication: A Feasibility Study on Selecting the Frequency and Matching Medium"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4340-1387","authenticated-orcid":false,"given":"Bilal","family":"Amin","sequence":"first","affiliation":[{"name":"Smart Sensors Laboratory, College of Medicine, Nursing Health Sciences, University of Galway, H91 TK33 Galway, Ireland"},{"name":"Electrical and Electronic Engineering, University of Galway, H91 TK33 Galway, Ireland"}]},{"given":"Muhammad Riaz ur","family":"Rehman","sequence":"additional","affiliation":[{"name":"Smart Sensors Laboratory, College of Medicine, Nursing Health Sciences, University of Galway, H91 TK33 Galway, Ireland"}]},{"given":"Muhammad","family":"Farooq","sequence":"additional","affiliation":[{"name":"Smart Sensors Laboratory, College of Medicine, Nursing Health Sciences, University of Galway, H91 TK33 Galway, Ireland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0988-5776","authenticated-orcid":false,"given":"Adnan","family":"Elahi","sequence":"additional","affiliation":[{"name":"Electrical and Electronic Engineering, University of Galway, H91 TK33 Galway, Ireland"}]},{"given":"Kevin","family":"Donaghey","sequence":"additional","affiliation":[{"name":"Aurigen Medical, Atlantic Technological University (ATU) Innovation Hub, H91 FD73 Galway, Ireland"}]},{"given":"William","family":"Wijns","sequence":"additional","affiliation":[{"name":"Smart Sensors Laboratory, College of Medicine, Nursing Health Sciences, University of Galway, H91 TK33 Galway, Ireland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4741-4302","authenticated-orcid":false,"given":"Atif","family":"Shahzad","sequence":"additional","affiliation":[{"name":"Smart Sensors Laboratory, College of Medicine, Nursing Health Sciences, University of Galway, H91 TK33 Galway, Ireland"},{"name":"Centre for Systems Modeling and Quantitative Biomedicine, University of Birmingham, Birmingham B15 2TT, UK"}]},{"given":"Patricia","family":"Vazquez","sequence":"additional","affiliation":[{"name":"Smart Sensors Laboratory, College of Medicine, Nursing Health Sciences, University of Galway, H91 TK33 Galway, Ireland"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1093\/eurheartj\/ehz859","article-title":"European Society of Cardiology: Cardiovascular disease statistics 2019","volume":"41","author":"Timmis","year":"2020","journal-title":"Eur. 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