Retinal prosthetic devices (RPDs) require miniaturized, biocompatible, and energy-efficient wireless links to enable reliable power delivery and data communication under harsh intraocular environments. This paper presents a smart-glass-enabled intraocular wireless power transfer (WPT) and communication platform based on an interdigitated spiral antenna integrated with an on-substrate rectifier, coated with an oil-infused biocompatible elastomer. The proposed implant is fabricated on a Rogers RT Duroid 6010 substrate with a compact size of 6.3 mm × 6 mm × 0.25 mm and achieves ultra-wideband (UWB) impedance matching from 2.2 to 8 GHz. Unlike conventional RPDs that rely on inductive coils or narrowband architectures, the proposed design enables simultaneous radiative near-field WPT and wideband communication within a single compact intraocular structure. A detailed electromagnetic analysis is conducted using a realistic eye model, which demonstrated robust impedance matching and stable transmission performance under eye rotation and transmitter (Tx)-receiver (Rx) antenna separation variations. The proposed WPT system achieved -22 dB power transfer efficiency with a Tx-to-Rx separation of 17 mm. The UWB Rx achieved a maximum measured peak gain greater than -14 dBi with a measured radiation efficiency of more than -24 dB across the 2–7 GHz frequency range. Furthermore, sensitivity analysis confirms that the antenna maintains reliable operation under ±20% variations in tissue permittivity and conductivity to account for inter-subject physiological variability. In addition, a WPT Tx is integrated into glasses to ensure wearability and to validate real-time rectification and LED illumination under saline-loaded conditions experimentally. To ensure compliance with safety regulations, a comprehensive safety analysis is conducted, including specific absorption rate and tissue heating. To assess long-term functional stability, in vitro aging studies of the oil-infused elastomer in phosphate-buffered saline at physiological and accelerated temperatures are conducted, followed by gravimetric, radio-frequency (RF), and spectroscopic analyses to verify sustained surface integrity, functional stability, and the absence of oil leaching over time.

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.