This work presents a water-substrate-based conformal implantable antenna (WSCIA) designed for Industrial Internet of Medical Things (IIoMT) applications. The antenna exhibits ultra-wideband (UWB) characteristics across the Industrial, Scientific, and Medical bands at 915 MHz and 2400 MHz, enabling efficient wireless power transfer and high-data-rate biotelemetry. It achieves a bandwidth of 510 MHz (0.71–1.23 GHz) in the 915 MHz band and 1.30 GHz (1.80–3.10 GHz) in the 2400 MHz band. The antenna exhibits strong radiation stability in varying tissue environments, ensuring reliable performance under realistic implantation conditions. Measured peak realized gains are –24.87 dBi at 915 MHz and –22.03 dBi at 2400 MHz, with corresponding radiation efficiencies of 0.76% and 0.80%. The specific absorption rate (SAR) analysis using an anatomically realistic human model confirms compliance with safety guidelines. Link margin and received power analyses confirm reliable telemetric communication at distances beyond 10 m for 915 MHz and 5 m for 2400 MHz, supporting high data rates of up to 120 Mb/s. Owing to the dielectric similarity between water and human tissue, the proposed WSCIA enables efficient electromagnetic (EM) energy transfer and, through 3D printing, offers a lightweight and cost-effective alternative to traditional substrate-based antenna designs. Collectively, the dual-UWB performance, radiation stability, low SAR, compact design, and frequency tunability make the proposed WSCIA a promising solution for next-generation IIoMT-based implants. Furthermore, its structural flexibility and stable EM performance in diverse environments make it suitable for anatomically constrained regions, particularly the scalp, heart, and gastrointestinal tract, where reliable wireless communication and safe long-term implantation are critical.

Physiological signals such as respiration and heart rate are critical indicators for real-time health monitoring. Although conventional contact-based sensors like electrocardiograms offer high accuracy, they are limited by discomfort, hygiene concerns, and poor long-term usability. Radar-based and wireless RF sensing technologies have emerged as promising non-contact alternatives; however, they face challenges such as environmental interference, line-of-sight constraints, and limited signal selectivity. Additionally, hardware complexity, phase noise, and low signal-to-noise ratio hinder performance in dynamic environments. To address these limitations, this study proposes a novel physiological sensing system based on spoof surface plasmonic (SSP) metamaterial structures. These SSP-based sensors offer a low-profile design, material compatibility, and strong surface wave confinement, along with radiative capabilities for short-range wireless communication. By integrating SSP waveguides with radiative elements, the system enables passive, indirect-contact, and reliable detection of vital signs, providing improved robustness over traditional radar-based solutions. Furthermore, the system supports remote sensing and IoT-based connectivity, enabling seamless integration into healthcare monitoring networks. Experimental validation confirms the system’s potential for unobtrusive health monitoring in clinical settings. This work lays the groundwork for metamaterial-assisted sensing systems in next-generation biomedical applications.

WiFi’s high data throughput and robust connectivity, combined with Integrated Sensing and Communication (ISAC), facilitate seamless real-time video transmission, ensuring minimal interference and high-quality imaging for clinical applications such as wireless capsule endoscopy (WCE). The proposed system incorporates a novel ultrawideband (UWB) conformal antenna with the 2.45 GHz band, specifically supporting a WiFi-based system to enable high-speed wireless communication within the human body. By leveraging ISAC, the system efficiently integrates real-time sensing and communication, optimizing data transmission while maintaining signal integrity in dynamic in-body environments. The capsule is equipped with a miniaturized camera module that captures high-resolution images and transmits video data in real-time to an external receiver via a low-latency WiFi communication module. A comprehensive system architecture was developed, integrating Internet of Medical Things (IoMT) connectivity, a cloud-based processing framework, and an optimized node-based transmission mechanism for seamless data relay. To evaluate the system’s performance, experiments were conducted in a realistic environment, simulating human tissue conditions. Results demonstrate video transmission over distances of up to 5 meters, ensuring reliable and high-fidelity endoscopic visualization. The experimental findings validate the feasibility of WiFi-powered WCE for continuous gastrointestinal monitoring, highlighting its potential for real-time diagnostics, remote healthcare, and telemedicine applications.

This paper introduces a water-substrate-based implantable antenna (WSIA) that can be easily adapted to 2-and 4-elements multiple-input multiple-output (MIMO) configurations for high-data-rate Internet of Medical Things (IoMT) devices. The proposed antenna operates in the 2.45-GHz industrial, scientific, and medical band for biotelemetry and in the 1.47-GHz midfield band for the seamless wireless powering of IoMT devices. Compared with previously reported implantable antennas, the proposed MIMO antenna element is ultra-miniaturized, achieved through high water permittivity and a circular ring-shaped radiator. Additionally, the antenna elements are strategically positioned for 2-and 4-ports MIMO configurations to achieve polarization diversity (PD), improving isolation and overall system efficiency. The antennas were optimized within a realistic capsule containing electronic components, sensors, and batteries and were subsequently fabricated and tested. In addition to satisfactory performance in terms of scattering parameters, isolation, gain, and polarization diversity, the proposed MIMO antenna systems exhibited significantly lower specific absorption rates (SARs) owing to water substrate, thereby offering improved user safety. Evaluation of the MIMO performance, focusing on the envelope correlation coefficient and diversity gain, yielded results within acceptable limits, even in diverse body environments. Moreover, a link-budget analysis revealed that the antennas can establish a reliable communication link at distances of 20 and 15 m at 1.47 and 2.45 GHz, respectively with high-data-rate of 100 Mb/s. Owing to the similarity between the electrical properties of water and human tissue, the proposed WSIAs efficiently transform radiated energy and, being 3D printable, offer significantly lower fabrication costs than conventional substrate-based designs. With advantages such as compact size, multi-band operations, PD, low SAR, and reduced fabrication costs, these antennas offer substantial benefits for IoMT implants, particularly for wireless capsule endoscopy.

Urinary incontinence, characterized by the loss of voluntary control over the urinary bladder muscles, significantly affects the patients’ quality of life. This study presents a novel, minimally invasive device-level solution for continuous urinary bladder pressure (UBP) monitoring, integrating advanced resistance-based strain sensor and antenna technologies with seamless Internet of Medical Things (IoMT) compatibility. A flexible ultra-wideband (UWB) antenna with compact size of 6 mm × 7 mm × 1.5 mm is designed for biotelemetric communication. Additionally, a strain sensor was developed using a self-fabricated non-conventional conductive ink with silver nanoparticles, whereas both the antenna and sensor were printed on a Polydimethylsiloxane substrate. Performance of the antenna alone and the integrated antenna system is validated through experiments in saline solution and minced pork muscle. Operating at a center frequency of 2.45 GHz the antenna showed a measured -10 dB bandwidth of 3.23 GHz (1.40 to 4.63 GHz) with a measured gain value of -27.68 dBi. Moreover, the strain sensor exhibited a significant resistance change of approximately 420 kΩ from 0% to 90% stretching, showcasing its high sensitivity to minor pressure variations. Rigorous tests, including stretch-and-hold, repeated stretching, hysteresis loss measurement, and time response analysis, confirmed the accuracy and durability of the sensor. Furthermore, a wireless biotelemetric link was established, demonstrating the system’s ability to wirelessly monitor sensor data over distances exceeding 2 meters. Finally, specific absorption rate and magnetic resonance imaging (MRI) compatibility analysis is evaluated to ensure safety of the system. This study underscores the potential of the proposed telemetry-enabled device to transform medical diagnostics, enhance patient outcomes, and redefine the management of urinary incontinence within the rapidly advancing IoMT landscape, representing a significant advancement in smart healthcare.

Leadless cardiac pacemakers (LCPs) enhance health technology by offering a minimally invasive and reliable solution for cardiac pacing; however, their reliance on batteries poses a challenge to achieving extended device longevity. This study proposes an efficient wireless power transfer (WPT) system for LCP devices, in which the dynamic misalignments caused by the natural contraction and relaxation of heart muscles during cardiac cycles and respiratory movements are characterized for the first time. The system comprised an off-body transmitter (Tx) and an in-body rectifier-integrated conformal receiver antenna (Rx). A single-band Tx is optimized to deliver the power wirelessly in the 915 MHz frequency band, whereas the Rx element is configured to offer dual-band characteristics at 433 MHz (data-telemetric mode) and 915 MHz (power reception mode). In addition to the peak gains of −30.6 and −24.8 dBi at the respective lower and higher frequency bands, the Rx exhibited a wireless power reception efficiency of up to 0.53% with a harvested voltage of more than 3 V at 55 mm Tx-Rx separation. The simulation results were experimentally validated in a heart-mimicking phantom, demonstrating the effectiveness of the proposed WPT system in maintaining robust power delivery even in the presence of misalignments induced by physiological motions. Moreover, the rectifier’s measured efficiency of 82% emphasizes its effective power delivery from the perspective of commercial pacemakers. In addition, a WPT-enabled real-time wireless biotelemetric communication link was established, highlighting the system’s potential as a versatile Internet of Medical Things (IoMT) platform for monitoring various real-time physiological parameters.

Multichannel neural monitoring systems are crucial in the accurate diagnosis and treatment of epilepsy by continuously recording neural activity, allowing precise identification of epileptic zones. These systems demand an ultrawideband (UWB) antenna with wireless power reception capability to facilitate high-data-rate communication and battery-free operation for the development of compact and long-lasting neural devices. This articel introduces a compact ($9\times 11\times 0$.25 mm3) battery-free implantable UWB system with an integrated rectifier for multichannel epilepsy monitoring, wirelessly powered by a novel 2.4 GHz smart cap-based transmitter (Tx) antenna. Extensive simulations and measurements are conducted to analyze the system’s performance. The implantable system exhibits a measured ultrawide bandwidth of 6.8 GHz (1.2–8 GHz) with peak gain values of −16.5, −23, and −24.1 dBi at 2.4, 4.8, and 5.8 GHz, respectively. The proposed wearable smart cap-based Tx antenna efficiently transfers power to the UWB implant system in various scenarios, including lateral and rotational misalignments, achieving a measured transmission coefficient$(|S_{21}|)$of −20.06 dB at a 15 mm distance while ensuring user comfort and mobility. Moreover, the compact rectifying circuit achieves a maximum conversion efficiency of 78.4% at a low input power of 6 dBm across a 2 k$\Omega $load. In addition, the safety of the system was validated using a realistic human head model to ensure compliance with the IEEE specific absorption rate limits. The features and performance metrics demonstrate that the proposed UWB implant system, powered by a wearable smart cap, offers a promising solution for safe, continuous, and battery-free multichannel epilepsy monitoring applications.

We introduced a circularly arranged Vivaldi endfire antenna array combined with nona-band rectifiers to enhance the capability of receiving electromagnetic power to supply power for Internet of Thing (IoT) devices. The rectifier encompasses frequencies of 0.9, 1.4, 1.8, 2.1, 2.4, 2.6, 3.5, 4.9, and 5.8 GHz, primarily covering telecom and Wi-Fi operating frequencies. Higher efficiency values at a lower input power of -10 dBm were achieved as 73.98%, 54.54%, 63.16%, 27.14%, 59.58%, 56.60%, 46.62%, 21.43, and 20.64% at 0.9, 1.4, 1.8, 2.1, 2.4, 2.6, 3.5, 4.9, and 5.8 GHz, respectively. In addition to the rectifier, we designed a wideband endfire Vivaldi antenna with a 3–8 dB gain over the operating frequencies, with an efficiency exceeding 80%. To further boost the received power, the antenna rectifier was transformed into an eight-element-based circular array, enabling multibeam and full-azimuth power reception coverage. We validated the performance of the rectifier and antenna by fabricating an energy-harvester array. Furthermore, we demonstrate the IoT device operation to illustrate the practical application of our proposed system.

Textiles integrated with electronics and long-range (LoRa) wireless technology are revolutionizing e-healthcare by enabling remote patient monitoring through wireless body area networks. This article presents a smart textile-based LoRa technology system for monitoring heart rate and predicting body temperature over both short and long distances. The system incorporates a LoRa module integrated with a smart textile, featuring sensors for photoplethysmography, electrocardiography, and body temperature monitoring. An embroidered monopole antenna seamlessly integrates into clothing, offering triple-band wideband operation at 433, 610, and 915 MHz with minimal susceptibility to human body effects and structural deformations. The proposed wearable antenna, assessed through specific absorption rate analysis, exhibits minimal exposure to electromagnetic radiation, ensuring user safety. The smart textile LoRa-enabled healthcare application (STLHA) monitors the received signal strength indicator, heart rate, and temperature data. Experimental results demonstrate effective outdoor communication ranges of up to 250 m at 915 MHz and 350 m at 433 MHz, with indoor ranges of up to 50 m. The STLHA offers a wireless solution for wearable devices, which enhances their functionality and usability in e-healthcare applications.

This paper presents a wireless link between an intraoral Tongue Drive System (iTDS) and a nearby receiver. The iTDS is a wireless and wearable assistive technology (AT) detects tongue gestures and allows individuals with severe physical disabilities to issue a set of user-defined tongue commands to access computers, smart-phone, and navigate powered wheelchairs. To mitigate the effects of external RF interference, the Tx can switch between three transmission bands (27 MHz, 433MHz, and 915 MHz), while sharing a dual-band antenna for the upper two bands and a coil for the lower band and battery charging to reduce size. Additionally, two adaptive matching networks are incorporated with the Tx at 433 MHz and 915 MHz, respectively, to maintain robustness of wireless link in the dynamic mouth environment. The adaptive matching mechanism utilizes a feedback for auto-tuning of the antennas' matchings. The adaptive triple-band Tx chip is implemented in a 5 V 0.35-pm standard CMOS process and a combination of simulation and measurement results have been presented.