{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T23:43:49Z","timestamp":1793144629861,"version":"4.5.0"},"reference-count":25,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,2,27]],"date-time":"2026-02-27T00:00:00Z","timestamp":1772150400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Science Fund for Excellent Young Scholars of China","award":["RK118QN23003"],"award-info":[{"award-number":["RK118QN23003"]}]},{"name":"Foundation of Jiangsu Specially Appointed Professor, Natural Science Research Startup Foundation of Nanjing University of Posts and Telecommunications","award":["NY223124"],"award-info":[{"award-number":["NY223124"]}]},{"name":"Jiangsu Provincial Team of Innovation and Entrepreneurship","award":["JSSCTD202351"],"award-info":[{"award-number":["JSSCTD202351"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>This work presents a highly compact triple-band multi-input-multi-output (MIMO) implantable antenna for wireless capsule endoscopy (WCE) and leadless cardiac pacemakers. The proposed antenna operates at industrial, scientific, and medical (ISM) bands of 2.400 to 2.480 GHz and 5.725 to 5.875 GHz for data telemetry and the wireless medical telemetry service (WMTS) band of 1.395 to 1.432 GHz for efficient wireless power transfer. The four-element design measures 8.5 \u00d7 8.5 \u00d7 0.26 mm3 and achieves low mutual coupling through a planar four-port configuration with optimized inter-element spacing. The antenna is integrated within realistic capsule devices containing batteries, sensors, and electronic components, and evaluated in both homogeneous and realistic heterogeneous body phantoms, including the large intestine and heart. The design yields maximum reflection coefficients of \u221226.15 dB, \u221215 dB, and \u221236.32 dB, \u221210 dB bandwidths of 260 MHz, 160 MHz, and 160 MHz, mutual coupling of \u221237.74 dB, \u221244.55 dB, \u221226.48 dB, and peak realized gains of \u221235 dBi, \u221225 dBi, and \u221215 dBi at 1.4 GHz, 2.45 GHz, and 5.8 GHz, respectively. Specific absorption rate (SAR) analysis satisfies implantation safety limits. Link budget analysis confirms reliable communication over distances &gt; 20 m in all bands with data rates up to 100 Mbps. MIMO channel parameters such as envelope correlation coefficient (ECC) and diversity gain (DG) remain within acceptable limits. Owing to its multi-band operation, miniaturization, and isolation, the proposed four-port antenna is a good candidate for next-generation WCE and leadless pacemaker systems.<\/jats:p>","DOI":"10.3390\/mi17030296","type":"journal-article","created":{"date-parts":[[2026,2,27]],"date-time":"2026-02-27T15:52:38Z","timestamp":1772207558000},"page":"296","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["A Highly Compact and Isolated Triple-Band MIMO Antenna for Wireless Capsule Endoscopy and Cardiac Implant"],"prefix":"10.3390","volume":"17","author":[{"given":"Tahir","family":"Bashir","sequence":"first","affiliation":[{"name":"College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guanjie","family":"Feng","sequence":"additional","affiliation":[{"name":"College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shunbiao","family":"Chen","sequence":"additional","affiliation":[{"name":"College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yunqi","family":"Cao","sequence":"additional","affiliation":[{"name":"College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1396-9692","authenticated-orcid":false,"given":"Wei","family":"Li","sequence":"additional","affiliation":[{"name":"College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China"},{"name":"School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1109\/MAP.2023.3301398","article-title":"Implantable and ingestible antenna systems: From imagination to realization [bioelectromagnetics]","volume":"65","author":"Basir","year":"2023","journal-title":"IEEE Antennas Propag. Mag."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4000610","DOI":"10.1109\/TIM.2022.3144212","article-title":"An implantable electronic device for monitoring fetal lung pressure in a Lamb model of congenital diaphragmatic hernia","volume":"71","author":"Robbiani","year":"2022","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"210","DOI":"10.1109\/MAP.2012.6293992","article-title":"A review of implantable patch antennas for biomedical telemetry: Challenges and solutions [wireless corner]","volume":"54","author":"Kiourti","year":"2012","journal-title":"IEEE Antennas Propag. Mag."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"4759","DOI":"10.1109\/TAP.2023.3266786","article-title":"A compact dual-band implantable antenna for wireless biotelemetry in arteriovenous grafts","volume":"71","author":"Zhang","year":"2023","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"4309","DOI":"10.1109\/TAP.2018.2836463","article-title":"A compact wideband flexible implantable slot antenna design with enhanced gain","volume":"66","author":"Das","year":"2018","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"6800","DOI":"10.1109\/TAP.2019.2927879","article-title":"A dual-band implantable rectenna for wireless data and power support at sub-GHz region","volume":"67","author":"Bakogianni","year":"2019","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1161","DOI":"10.1109\/TAP.2019.2938591","article-title":"A miniaturized dual-band implantable antenna system for medical applications","volume":"68","author":"Faisal","year":"2020","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1140","DOI":"10.1109\/TAP.2019.2938573","article-title":"Metamaterial-loaded compact high gain dual-band circularly polarized implantable antenna system for multiple biomedical applications","volume":"68","author":"Zada","year":"2020","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3146","DOI":"10.1109\/TAP.2023.3244035","article-title":"Capsule endoscopic MIMO antenna with radiation pattern and polarization diversity","volume":"71","author":"Iqbal","year":"2023","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Shunbiao, C., Bashir, T., and Li, W. (2025). Implantable MIMO Antenna for WMTS and ISM Bands in Leadless Cardiac Pacemaker System. Proceedings of the 2025 18th IEEE United Conference on Millimeter Waves and Terahertz Technologies, IEEE.","DOI":"10.1109\/UCMMT67044.2025.11287781"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3123","DOI":"10.1109\/TAP.2023.3243984","article-title":"Miniaturized four-port MIMO implantable antenna for high-data rate wireless-capsule-endoscopy applications","volume":"71","author":"Shah","year":"2023","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Bashir, T., Feng, G., Shunbiao, C., and Li, W. (2025). Compact Dual-Band 3D MIMO Antenna for Wireless Biomedical Implantable Devices. Proceedings of the 2025 18th IEEE United Conference on Millimeter Waves and Terahertz Technologies, IEEE.","DOI":"10.1109\/UCMMT67044.2025.11286680"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1723","DOI":"10.1109\/LAWP.2016.2528987","article-title":"Small-size dual antenna implantable system for biotelemetry devices","volume":"15","author":"Xiao","year":"2016","journal-title":"IEEE Antennas Wireless Propag. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"226","DOI":"10.1109\/JERM.2018.2871458","article-title":"A miniaturized four-element MIMO antenna with EBG for implantable medical devices","volume":"2","author":"Fan","year":"2018","journal-title":"IEEE J. Electromagn. RF Microw. Med. Biol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1053","DOI":"10.1109\/JMW.2025.3583891","article-title":"Radiation diversity enabled self-isolated compact dual-band cubic MIMO antenna for wireless biomedical implants in variable and dynamic environments","volume":"5","author":"Bashir","year":"2025","journal-title":"IEEE J. Microw."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1394","DOI":"10.1109\/LAWP.2021.3081477","article-title":"Miniaturized dual antenna system for implantable biotelemetry application","volume":"20","author":"Singh","year":"2021","journal-title":"IEEE Antennas Wireless Propag. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1260","DOI":"10.1109\/TAP.2020.3016483","article-title":"Quadrilateral spatial diversity circularly polarized MIMO cubic implantable antenna system for biotelemetry","volume":"69","author":"Kaim","year":"2021","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"30398","DOI":"10.1109\/JIOT.2025.3570779","article-title":"Dual-polarized water-substrate-based MIMO implantable antenna for IoMT-enabled biotelemetric devices","volume":"12","author":"Abbas","year":"2025","journal-title":"IEEE Internet Things J."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"14889","DOI":"10.1038\/s41598-025-99609-1","article-title":"Development of an efficient mid-field wireless power transmission system for biotelemetric IoT medical devices","volume":"15","author":"Abbas","year":"2025","journal-title":"Sci. Rep."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"7257","DOI":"10.1109\/TAP.2017.2758161","article-title":"Single-layer dual-\/tri-band inverted F antennas for conformal capsule type of applications","volume":"65","author":"Bao","year":"2017","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2816","DOI":"10.1109\/TAP.2017.2694700","article-title":"A wideband circularly polarized conformal endoscopic antenna system for high-speed data transfer","volume":"65","author":"Das","year":"2017","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"31031","DOI":"10.1109\/ACCESS.2019.2902981","article-title":"A wide-band tissue numerical model for deeply implantable antennas for RF powered leadless pacemakers","volume":"7","author":"Asif","year":"2019","journal-title":"IEEE Access"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"7515","DOI":"10.1109\/TAP.2024.3454434","article-title":"A compact dual-band implantable MIMO antenna for wireless capsule endoscopy","volume":"72","author":"Iqbal","year":"2024","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"6374","DOI":"10.1109\/TAP.2024.3423436","article-title":"Compact dual-band MIMO implantable antenna system for high-data-rate cortical visual prostheses applications","volume":"72","author":"Ali","year":"2024","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_25","unstructured":"(2019). IEEE Standard for Safety Levels with Respect to Human Exposure to Electric, Magnetic, and Electromagnetic Fields, 0 Hz to 300 GHz (Standard No. IEEE Standard C95.1-2019)."}],"container-title":["Micromachines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/3\/296\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,27]],"date-time":"2026-02-27T16:04:52Z","timestamp":1772208292000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/3\/296"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,27]]},"references-count":25,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2026,3]]}},"alternative-id":["mi17030296"],"URL":"https:\/\/doi.org\/10.3390\/mi17030296","relation":{},"ISSN":["2072-666X"],"issn-type":[{"value":"2072-666X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,27]]}}}