This article proposes an efficient and complete wireless power transfer (WPT) system (WPTS) for multipurpose biomedical implants. The WPTS is composed of a self-diplexing implantable antenna, efficient rectifier, and WPT transmitter (WPT Tx). The proposed system is capable of simultaneously transmitting recorded data and recharging the batteries of the devices (so as to elongate the implant life). The WPT Tx occupies dimensions of 50 ×50 ×1.6 mm ³ and is optimized to effectively transfer power at 1470 MHz to a 55-mm deep implantable device. An efficient and compact ( 3.4 ×6.7 mm ² ) rectifier is used at 1470 MHz to convert the harvested RF power into a useful direct current (dc) power. The proposed rectifier circuit exhibits a high conversion efficiency of 50% even at an input power of -14 dBm and maximum efficiency of 76.1% at 2 dBm. The proposed self-diplexing implantable antenna occupies small dimensions (9.4 mm ³ ) and operates at 915 and 1470 MHz by exciting ports 1 and 2, respectively. The biotelemetry operation is performed using a 915 MHz band (port 1), and the rectifier circuit is connected to port 2 (1470 MHz) to perform wireless powering. The simulated results are validated by examining the individual elements (WPT Tx, rectifier, and self-diplexing antenna) and overall WPTS in a saline solution and minced pork. The results prove that the proposed scheme is suitable for biotelemetry and wireless powering of biomedical implants.

Atrial Fibrillation (AF) the most commonly occurring type of cardiac arrhythmia is one of the main causes of morbidity and mortality worldwide. The timely diagnosis of AF is an equally important and challenging task because of its asymptomatic and episodic nature. In this paper, state-of-the-art ECG data-based machine learning models and signal processing techniques applied for auto diagnosis of AF are reviewed. Moreover, key biomarkers of AF on ECG and the common methods and equipment used for the collection of ECG data are discussed. Besides that, the modern wearable and implantable ECG sensing technologies used for gathering AF data are presented briefly. In the end, key challenges associated with the development of auto diagnosis solutions of AF are also highlighted. This is the first review paper of its kind that comprehensively presents a discussion on all these aspects related to AF auto-diagnosis in one place. It is observed that there is a dire need for low energy and low cost but accurate auto diagnosis solutions for the proactive management of AF.

This article presents a low-profile multiple-input–multiple-output (MIMO) implantable antenna system, including a capsule endoscopy and a scalp implantation at medical implant communication service (MICS) band (402–405 MHz), and industrial, scientific, and medical (ISM) band (433.1–438.8 MHz). It consists of two elements with an edge-to-edge gap of $0.0018\lambda _{g}$ and overall dimensions of $\pi \times (5.65)^{2} \times 0.13$ mm ³ and is placed on a 0.13 mm-thick RO3010 ( $\epsilon _{r} = 10.2$ and tan $\delta = 0.0022$ ) substrate. The antenna is integrated with batteries, sensors, and electronic components in two different types of implantable devices (capsule and flat-type devices). The simulation result shows that the antenna has a fractional bandwidth (FBW) of 33.9%, a maximum realized gain of −30 dBi, and isolation of more than 26 dB. The fabricated prototype is measured in a saline solution and minced pork meat. The measured results are found in good accordance with simulations. The antenna parameters are calculated and showed a significant independence between the radiators. A link budget is estimated to be 78 Mb/s for a distance of 20 m. Thus, the proposed antenna is considered as a promising solution for high-data-rate medical applications such as capsule endoscopy, live surgeries, and other biomedical applications where the high data rate is required.

Design of a compact wideband circularly polarized (CP) multiple-input multiple-output (MIMO) antenna with polarization diversity is proposed and characterized for off-body communication. The antenna is based on a simple coplanar waveguide (CPW)-fed monopole extension of the microstrip line. The orthogonal field components required by CP are induced using a simply modified right/left side ground plane. In particular, a stub extending from the ground plane along the length of the microstrip line generates the vertical component, whereas the current along the width of the ground plane contributes to the horizontal components. To obtain a unidirectional radiation pattern in the off-body direction and to reduce the sensitivity to the human body loading effects, a flat reflector printed on a high permittivity flexible substrate is applied. The simple topology of the antenna can be described by a few adjustable parameters, which facilitates its EM design closure. Prior to the experimental validation in the free space and on the body, the antenna is optimized at the full-wave level of description for all major performance figures. The overall footprint of the antenna radiator is only Ls × Ws = 0.24 λ0 × 0.64 λ0 = 0.15 λ02. The proposed MIMO antenna features |S11|≤ -10 dB, average isolation |S21|≤ -22 dB, and axial ratio (AR)and axial ratio 3 dB from 5.2 GHz to 6.3 GHz with 100% bandwidth overlap between the impedance and axial ratio bandwidths. The envelope correlation coefficient (ECC) is less than 0.004 with the maximum diversity gain (DG) of approximately 9.99 dB. Moreover, the antenna maintains a high efficiency of up to 90% when loaded on the body, and a low specific absorption rate (SAR).

The ever-growing demand for low power, high performance, cost-effective, low-profile, and highly integrated wireless systems for emerging applications has triggered the need for the enormous innovations in wireless transceiver systems, components, architectures and technologies. This is especially valid for the antenna which is an integral component of the wireless transceiver systems and contributes significantly in determining their overall performance. Antenna-on-Chip (AoC) is an alternative antenna technology, which has drawn a substantial attention in recent days because of its various benefits over off-chip antenna technology. A few of these benefits include miniaturization, low power, low cost, and high integration of the wireless modules. Motivated by these valuable advantages and to unveil the true potential of the AoCs, this article presents, for the first time, a comprehensive survey of the suitability, advantages, and challenges of the AoCs for the emerging wireless applications such as 5th generation (5G) Wireless Systems, Internet-of-Things (IoT) Wireless Devices and Systems, Wireless Sensor Networks (WSNs), Wireless Interconnects, Wireless Energy Transfer, Radio Frequency (RF) Energy Harvesting, Biomedical Implants, Unmanned Aerial Vehicles (UAVs), Autonomous vehicles, Innovative characterization methods for Integrated Circuits (ICs) and Antennas, and Smart City. In addition, this article presents the current state-of-the-art of the AoC’s applications by classifying their applications in Millimeter-Wave (MM-Wave) band, Terahertz (THz) band, and low-frequency bands. The article also investigates and describes some useful methods for the mitigation of the challenges and issues posed by the emerging applications for the realization of the AoCs in a systematic manner. A concise description of the future directions of the AoCs with respect to each emerging application is also a part of this article. It is expected that this well-structured and organized survey will not only act as an excellent source of scholarship for the relevant research community, but also open up a world of novel research opportunities.

This study presents a multi-band conformal antenna based endoscopic system for robust biotelemetry communications, which covers five important bands, including the MedRadio (401–406 MHz), Industrial, Scientific, and Medical (ISM) (433.1–434.8 MHz, 868–868.6 MHz, 902–928 MHz), and midfield (1200 MHz) bands. These bands are intended for functions such as biotelemetry, power saving, and wireless power transfer (WPT). The proposed antenna is printed on a flexible material Rogers ULTRALAM with a thickness of only 0.1 mm, which can be easily wrapped around the inner wall of a capsule. Owing to the insertion of the via and open-ended meandered slots in the radiator and in the ground plane, the footprints of the suggested antenna reduce considerably. In the flat form, the antenna is 57 mm3 in volume, whereas in the wrapped form, it is only 48.98 mm3 in volume. In a homogeneous muscle phantom, the proposed conformal antenna shows a 27.46% wider bandwidth at 402 MHz, whereas it shows a 13.2% and 5.42% bandwidth at 915 MHz and 1200 MHz, respectively. Furthermore, the specific absorption rate investigation at three resonance frequencies in various implanted locations shows compliance with the IEEE guidelines, thereby guaranteeing human safety. For measurements, a 3D capsule with batteries and circuitry is devised using a 3D printer, and the simulation results are experimentally validated in a box containing minced pork. Finally, the robustness of the communication link is confirmed through the link budget analysis at 1 Mb/s. The conformal design concept, omni-directional radiations, and multi-band functionality with a wider bandwidth in the MedRadio band of the suggested antenna will enhance the diversity of the capsule endoscope and be a good addition to the field of biotelemetry.