{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,26]],"date-time":"2026-05-26T12:07:14Z","timestamp":1779797234341,"version":"3.53.1"},"reference-count":27,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,5,26]],"date-time":"2026-05-26T00:00:00Z","timestamp":1779753600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>The convergence of artificial intelligence, biotechnology, and the Internet of Bio-Nano Things (IoBNT) is enabling the creation of a new generation of intelligent in-body medical devices for continuous diagnosis and monitoring. In this context, a compact, wideband, circularly polarized conformal microstrip antenna is proposed for capsule endoscopy applications. The antenna is integrated along the inner wall of a 10 mm-diameter capsule and achieves an impedance bandwidth of 2.06\u20135.39 GHz (89.39%), maintaining stable matching under varying biological tissue conditions. A 3 dB axial ratio bandwidth (ARBW) of 2.31\u20133.14 GHz (30.45%) ensures reliable circular polarization and robust wireless communication in lossy and dynamic in-body environments. To extend beyond conventional electromagnetic analysis, a physics-informed neural network (PINN) framework is introduced to model the thermal response of biological tissues based on the governing bioheat equation. This AI-driven approach enables fast and generalizable prediction of temperature rise under varying operational conditions without repeated numerical simulations. At 2.45 GHz, the antenna exhibits a maximum gain of \u221231.1 dBi with a radiation efficiency of approximately \u221234 dB, consistent with in-body propagation constraints. Simulation and experimental results in realistic tissue phantoms, including muscle, small intestine, large intestine, and stomach, confirm stable wideband and polarization performance. Specific absorption rate (SAR) analysis demonstrates compliance with IEEE C95.1-2019 safety limits, while link budget evaluation validates reliable telemetry over a 1\u20133 m communication range. The integration of advanced antenna design with physics-informed machine learning provides a scalable framework for intelligent, safe, and adaptive IoBNT-enabled capsule endoscopy systems.<\/jats:p>","DOI":"10.3390\/bioengineering13060620","type":"journal-article","created":{"date-parts":[[2026,5,26]],"date-time":"2026-05-26T11:02:51Z","timestamp":1779793371000},"page":"620","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Wideband Circularly Polarized Conformal Antenna with Physics-Informed Neural Network Modeling for IoBNT Capsule Endoscopy"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2030-6141","authenticated-orcid":false,"given":"Pariya","family":"Nasirishehni","sequence":"first","affiliation":[{"name":"Faculty of Engineering and Technology, Imam Khomeini International University (IKIU), Qazvin 34148-96818, Iran"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5312-6497","authenticated-orcid":false,"given":"Mohammad (Behdad)","family":"Jamshidi","sequence":"additional","affiliation":[{"name":"Faculty of Engineering and Information Technology, University of Technology Sydney (UTS), Sydney, NSW 2007, Australia"},{"name":"Research and Development Department, MetaMax, Sydney, NSW 2010, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0158-9526","authenticated-orcid":false,"given":"Mehdi","family":"Mehranpour","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, University of Mohaghegh Ardabili (UMA), Ardabil 56199-11367, Iran"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"417","DOI":"10.1038\/35013140","article-title":"Wireless Capsule Endoscopy","volume":"405","author":"Iddan","year":"2000","journal-title":"Nature"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1109\/MCOM.2015.7060516","article-title":"The Internet of Bio-Nano Things","volume":"53","author":"Akyildiz","year":"2015","journal-title":"IEEE Commun. Mag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"109970","DOI":"10.1016\/j.compbiomed.2025.109970","article-title":"Revolutionizing Biological Digital Twins: Integrating Internet of Bio-Nano Things, Convolutional Neural Networks, and Federated Learning","volume":"189","author":"Jamshidi","year":"2025","journal-title":"Comput. Biol. Med."},{"key":"ref_4","unstructured":"Hall, P., and Hao, Y. (2012). Antennas and Propagation for Body-Centric Wireless Communications, Artech House. [2nd ed.]."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Guo, L., Sultan, K., Xue, F., and Abbosh, A. (2025). The Impact of Dual-Wavefront Propagation of Electromagnetic Waves in Bio-Tissues on Imaging and In-Body Communications. Biosensors, 15.","DOI":"10.3390\/bios15100667"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"6537","DOI":"10.1109\/TAP.2022.3161342","article-title":"Conformal Folded Inverted-F Antenna with Quasi-Isotropic Radiation Pattern for Robust Communication in Capsule Endoscopy Applications","volume":"70","author":"Wang","year":"2022","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"10233","DOI":"10.1109\/TAP.2022.3197272","article-title":"915 MHz Miniaturized Loop Conformal Antenna for Capsule Endoscope","volume":"70","author":"Xiao","year":"2022","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"10270","DOI":"10.1109\/TAP.2022.3195556","article-title":"A Conformal Four-Antenna Module for Capsule Endoscope MIMO Operation","volume":"70","author":"Wang","year":"2022","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"5724","DOI":"10.1109\/TAP.2024.3411703","article-title":"Conformal MIMO Ultrawideband Antenna Design for High-Speed Wireless Telemetry in Capsule Endoscopy Systems","volume":"72","author":"Chang","year":"2024","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"5333","DOI":"10.1109\/TAP.2025.3567502","article-title":"Miniaturized Quad-Band Implantable Antenna for Wireless Capsule Endoscopy and Deep Tissue Monitoring Applications","volume":"73","author":"Nasir","year":"2025","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"30644","DOI":"10.1038\/s41598-025-15591-8","article-title":"Compact Wideband Implantable Antenna for Wireless Capsule Endoscopy Application in the 2.45 GHz ISM Band","volume":"15","author":"Mohan","year":"2025","journal-title":"Sci. Rep."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1989","DOI":"10.1109\/OJAP.2025.3611662","article-title":"A Compact Tissue-Insensitive Ultra-Wideband Implantable Antenna for Wireless Power Transfer in Implantable Medical Devices","volume":"6","author":"Essa","year":"2025","journal-title":"IEEE Open J. Antennas Propag."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2407","DOI":"10.1109\/TAP.2014.2307341","article-title":"Capacitively Loaded Circularly Polarized Implantable Patch Antenna for ISM Band Biomedical Applications","volume":"62","author":"Liu","year":"2014","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_14","first-page":"3027","article-title":"Compact Circularly Polarized Microstrip Antenna for Capsule Endoscopy","volume":"67","author":"Li","year":"2019","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"53868","DOI":"10.1109\/JIOT.2025.3621421","article-title":"Physics-Informed Neural Networks for Bio-Nano Digital Twins: A Multi-Model Framework with IoBNT Integration","volume":"12","author":"Jamshidi","year":"2025","journal-title":"IEEE Internet Things J."},{"key":"ref_16","unstructured":"Jamshidi, M. (2025). Federated and Physics-Informed AI Models for Real-Time Bio-Nano Digital Twins Using IoBNT. [Ph.D. Thesis, University of Technology Sydney (UTS)]."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2231","DOI":"10.1088\/0031-9155\/41\/11\/001","article-title":"The Dielectric Properties of Biological Tissues: I. Literature Survey","volume":"41","author":"Gabriel","year":"1996","journal-title":"Phys. Med. Biol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"171346","DOI":"10.1109\/ACCESS.2019.2954823","article-title":"Synopsis of IEEE Std C95.1\u2122-2019 \u201cIEEE Standard for Safety Levels with Respect to Human Exposure to Electric, Magnetic, and Electromagnetic Fields, 0 Hz to 300 GHz\u201d","volume":"7","author":"Bailey","year":"2019","journal-title":"IEEE Access"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"154197","DOI":"10.1016\/j.aeue.2022.154197","article-title":"A Miniaturized Wideband Wearable Antenna with Circular Polarization for Medical Application","volume":"150","author":"Vaezi","year":"2022","journal-title":"AEU\u2013Int. J. Electron. Commun."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"686","DOI":"10.1016\/j.jcp.2018.10.045","article-title":"Physics-Informed Neural Networks: A Deep Learning Framework for Solving Forward and Inverse Problems Involving Nonlinear Partial Differential Equations","volume":"378","author":"Raissi","year":"2019","journal-title":"J. Comput. Phys."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"128780","DOI":"10.1016\/j.applthermaleng.2025.128780","article-title":"Microwave Defrosting Control Logic Derived from Infrared Matrix Temperature Sensor Data Using Physics-Informed Neural Networks","volume":"281","author":"Cheng","year":"2025","journal-title":"Appl. Therm. Eng."},{"key":"ref_22","unstructured":"Balanis, C.A. (2016). Antenna Theory: Analysis and Design, John Wiley & Sons. [4th ed.]."},{"key":"ref_23","first-page":"174","article-title":"A Designer\u2019s Guide to Microstrip Line","volume":"16","author":"Bahl","year":"1977","journal-title":"Microwaves"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2480","DOI":"10.1109\/TMTT.2009.2029664","article-title":"Dielectric Loaded Impedance Matching for Wideband Implanted Antennas","volume":"57","author":"Dissanayake","year":"2009","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"International Commission on Non-Ionizing Radiation Protection (2020). ICNIRP guidelines for limiting exposure to electromagnetic fields. Health Phys., 118, 483\u2013524.","DOI":"10.1097\/HP.0000000000001210"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Song, Z., Xu, X., Shi, Y., and Wang, L. (2024). Design of a Compact Circularly Polarized Implantable Antenna for Capsule Endoscopy Systems. Sensors, 24.","DOI":"10.3390\/s24123960"},{"key":"ref_27","first-page":"186","article-title":"Smart Capsules for Sensing and Sampling the Gut: Status, Challenges and Prospects","volume":"73","author":"Berean","year":"2023","journal-title":"Gut"}],"container-title":["Bioengineering"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2306-5354\/13\/6\/620\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,26]],"date-time":"2026-05-26T11:41:10Z","timestamp":1779795670000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2306-5354\/13\/6\/620"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,26]]},"references-count":27,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["bioengineering13060620"],"URL":"https:\/\/doi.org\/10.3390\/bioengineering13060620","relation":{},"ISSN":["2306-5354"],"issn-type":[{"value":"2306-5354","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,26]]}}}