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At present, the performance of the traditional centralized coil antenna used for radio frequency identification(RFID) detection and localization of underground cables is insufficient, which seriously restricts the improvement of its detection and localization distance. A new type of high field strength distributed RFID coil antenna structure was proposed. Based on the derivation of antenna related electrical parameters, the magnetic field strength of the coil antenna was taken as the objective function, and its quality factor was fixed as the constraint condition. Particle swarm optimization algorithm was employed to optimize the number of turns of the coil antenna and the turn spacing between adjacent two turns. Finally, an experimental test platform was built. The test results show that compared with the traditional centralized RFID coil antenna, the distributed RFID coil antenna increases the reading distance by 33. 3%, significantly enhances the received signal strength indicator (RSSI) at the same distance, and helps to improve the accuracy of the underground RFID localization method based on RSSI, which provides an important reference for the application of RFID detection and localization of underground cables. [ABSTRACT FROM AUTHOR]

In recent years, implantable sensors have been extensively researched since they allow localized sensing at an area of interest (e.g., within the vicinity of a surgical site or other implant). They allow unobtrusive and potentially continuous sensing, enabling greater specificity, early warning capabilities, and thus timely clinical intervention. Wireless remote interrogation of the implanted sensor is typically achieved using radio frequency (RF), inductive coupling or ultrasound through an external device. Two categories of implantable sensors are available, namely active and passive. Active sensors offer greater capabilities, such as on-node signal and data processing, multiplexing and multimodal sensing, while also allowing lower detection limits, the possibility to encode patient sensitive information and bidirectional communication. However, they require an energy source to operate. Battery implantation, and maintenance, remains a very important constraint in many implantable applications even though energy can be provided wirelessly through the external device, in some cases. On the other hand, passive sensors offer the possibility of detection without the need for a local energy source or active electronics. They also offer significant advantages in the areas of system complexity, cost and size. In this review, implantable passive sensor technologies will be discussed along with their communication and readout schemes. Materials, detection strategies and clinical applications of passive sensors will be described. Advantages over active sensor technologies will be highlighted, as well as critical aspects related to packaging and biocompatibility. [ABSTRACT FROM AUTHOR]

Diffusion magnetic resonance imaging (dMRI) allows for a non-invasive visualization and quantitative assessment of white matter architecture in the brain by characterizing restrictions on the random motion of water molecules. Ultra-high field MRI scanners, such as those operating at 7 Tesla (7T) or higher, can boost the signal-to-noise ratio (SNR) to improve dMRI compared with what is attainable at conventional field strengths such as 3T or 1.5T. However, wavelength effects at 7T cause reduced transmit magnetic field efficiency in the human brain, mainly in the posterior fossa, manifesting as signal dropouts in this region. Recently, we reported a simple approach of using a wireless radiofrequency (RF) surface array to improve transmit efficiency and signal sensitivity at 7T. In this study, we demonstrate the feasibility and effectiveness of the RF enhancer in improving in vivo dMRI at 7T. The electromagnetic simulation results demonstrated a 2.1-fold increase in transmit efficiency with the use of the RF enhancer. The experimental results similarly showed a 1.9-fold improvement in transmit efficiency and a 1.4-fold increase in normalized SNR. These improvements effectively mitigated signal dropouts in regions with inherently lower SNR, such as the cerebellum, resulting in a better depiction of principal fiber orientations and an enhanced visualization of extended tracts. [ABSTRACT FROM AUTHOR]

This document describes the adaptation of a clamshell inductive current coupler for online reflectometry testing (both frequency-domain reflectometry and spread spectrum time-domain reflectometry) to evaluate cable anomalies. The life span of safety-critical nuclear power plant cables is initially qualified for 40 years in accordance with IEEE 383 without additional testing. As plants extend their operating licenses to 60 and 80 years, justification for continued safe operation includes cable test and condition monitoring (CM) programs. Test programs traditionally involve manual interventions to disconnect the cables, perform one or several tests, then reconnect the systems, usually during refueling outages occurring only every two years. Offline testing poses an operational burden that can be minimized by online testing. This work investigates the adaptation of a clamshell inductive current coupler to inject a signal onto a cable conductor and listen for a reflected signal indicative of a damaged condition. The coupler provides >60 dB of protection, thereby allowing tests on cables up to 10 kV or more. Although the clamshell coupler is a known commercial product for cable performance testing, its use for energized cable CM constitutes a novel use case.

Real-time data transmission and reliable operation are essential for a tsunami monitoring system to provide effective data. In this study, a novel real-time tsunami monitoring system is designed based on a submersible mooring system. This system is equipped with a data acquisition and tsunami wave identification algorithm, which can collect the measured data of the pressure sensor and detect a tsunami wave in real time. It adopts the combination design of underwater inductive coupling transmission and a redundant BeiDou communication device on the water surface to ensure the reliability of real-time data transmission. Compared with traditional tsunami monitoring buoys, it has the advantages of reliable communication, good concealment, high security, and convenient deployment, recovery, and maintenance. The results of laboratory and sea tests show that the system has high reliability of data transmission, stable overall operation of the system, and good application prospects in the field of real-time tsunami monitoring and early warning. [ABSTRACT FROM AUTHOR]

We present a machine learning driven system to monitor joint flexion angles during dynamic motion, using a wearable loop-based sensor. Our approach uses wearable loops to collect transmission coefficient data and an Artificial Neural Network (ANN) with fine-tuned parameters to increase accuracy of the measured angles. We train and validate the ANN for sagittal plane flexion of a leg phantom emulating slow motion, walking, brisk walking, and jogging. We fabricate the loops on conductive threads and evaluate the effect of fabric drift via measurements in the absence and presence of fabric. In the absence of fabric, our model produced a root mean square error (RMSE) of 5.90°, 6.11°, 5.90°, and 5.44° during slow motion, walking, brisk walking, and jogging. The presence of fabric degraded the RMSE to 8.97°, 7.21°, 9.41°, and 7.79°, respectively. Without the proposed ANN method, errors exceeded 35.07° for all scenarios. Proof-of-concept results on three human subjects further validate this performance. Our approach empowers feasibility of wearable loop sensors for motion capture in dynamic, real-world environments. Increasing speed of motion and the presence of fabric degrade sensor performance due to added noise. Nevertheless, the proposed framework is generalizable and can be expanded upon in the future to improve upon the reported angular resolution. [ABSTRACT FROM AUTHOR]

Musculoskeletal disorders are among the main causes of disease‐associated disability. Moreover, the incidence and prevalence of osteoporosis and osteoarthritis, as well as the risk of bone fractures and the need for joint replacements, are expected to increase with longer life expectancy. New approaches based on electromagnetic stimulation have been developed, aiming to shorten bone healing time, attenuate osteoporosis and osteoarthritis, and increase implants' osseointegration. Inductive coupling (IC), a non‐invasive methodology to deliver magnetic stimuli, has reached clinical trials and some clinical practices but is not yet considered a standard procedure. Indeed, its feasibility in clinical use is still under discussion, and optimal stimulation parameters are fairly undefined. This comprehensive review describes the research trends and applicability of IC‐based therapeutics for musculoskeletal disorders, and starts identifying top‐performing magnetic stimulation parameters. Insights into the magnetic stimuli setups that promote osteogenesis are provided, based on pre‐clinical and clinical evidence from 117 in vivo studies in animal models and human patients. Potential cellular and molecular biomechanisms mediating IC‐induced effects on osteoblasts and osteoclasts are also explored. The transversal knowledge herein delivered will hopefully support innovative designs and medical devices that will implement IC stimulation as a clinical standard and effective therapeutic for musculoskeletal disorders. [ABSTRACT FROM AUTHOR]

Electric Vehicles (EVs) are powered by a battery mounted in the vehicle, which powers the motor and drives the wheels. Most commercial EVs can be charged by plugging them into a charging station. Such conductive recharging has various drawbacks, including physical plugging of the cable, safety concerns, and charging time. Manually charging EVs might be dangerous due to the chance of an electric spark or disaster. Advances in Wireless Power Transfer (WPT) demonstrate the capacity to transfer significant amounts of electricity over short and medium-range distances. The ultimate purpose of this paper is to improve the efficacy of electric car wireless charging systems. Here, a hybrid optimization-based Artificial Neural Network (ANN) model is applied to improve the efficacy of the WPT model in EVs. To optimize the weights of the ANN classifier, a hybrid approach termed as Grasshopper-Assisted Elephant Herd Optimization (GA-EHO) method is proposed. The GA-EHO is derived through the hybridization of Elephant Herd Optimization (EHO) Algorithm and the Grasshopper Optimization Algorithm (GOA) techniques. Finally, the experimental study reveals that at 70% learning rate, the proposed ANN system achieves a minimal MSE value of 0.0528, which is lower than other current classifiers, such as SVM, LSTM, and CNN. [ABSTRACT FROM AUTHOR]

In this study, a multiwalled carbon nanotube (MWCNT) dispersion is used as an ink for a single-nozzle inkjet printing system to produce a planar coil that can be used to determine strain wirelessly. The MWCNT dispersion is non-covalently functionalized by dispersing the CNTs in an anionic surfactant, namely sodium dodecyl sulfate (SDS). The fabrication parameters, such as sonication energy and centrifugation time, are optimized to obtain an aqueous suspension suitable for an inkjet printer. Planar coils with different design parameters are printed on a flexible polyethylene terephthalate (PET) polymer substrate. The design parameters include a different number of windings, inner diameter, outer diameter, and deposited layers. The electrical impedance spectroscopy (EIS) analysis is employed to characterize the printed planar coils, and an equivalent electrical circuit model is derived based on the results. Additionally, the radio frequency identification technique is utilized to wirelessly investigate the read-out mechanism of the printed planar MWCNT coils. The complex impedance of the inductively coupled sensor undergoes a shift under strain, allowing for the monitoring of changes in resonance frequency and bandwidth (i.e., amplitude). The proposed wireless strain sensor exhibits a remarkable gauge factor of 22.5, which is nearly 15 times higher than that of the wireless strain sensors based on conventional metallic strain gauges. The high gauge factor of the proposed sensor suggests its high potential in a wide range of applications, such as structural health monitoring, wearable devices, and soft robotics. [ABSTRACT FROM AUTHOR]

Long-term daily-life body signal monitoring offers numerous advantages, such as timely response to health alerts, diseases monitoring, and reducing time and expenses related to clinical trials. Access to physiological data can be achieved with low-cost and comfortable wireless wearable sensors. In our previous publication, we reported a low-cost, easy to implement, and unobtrusive wireless resistive analog passive (WRAP) sensor to provide a feasible bio-signal monitoring technique by using a pair of printed spiral coils (PSC) in a near field connection. Sensitivity, defined as the response to the transducer, is a critical feature in the establishment of a reliable system. In the previous publication, we presented the utilization of a Genetic Algorithm to design a pair of coils and related components to maximize sensitivity. Although the coils' misalignment can significantly affect the optimized sensitivity, it was not incorporated into the optimization process. This paper focuses on optimizing the coils and components in order to maximize both their sensitivity and their resilience against movements of the PSC pair. In a square-shaped pair comprising a primary coil of 60 mm and a secondary coil of 20 mm dimensions, we found that the sensitivity is maximized at 1.3 mƱ for a 16 mm axial distance. Additionally, it remains above 0.65 mƱ within ±11.25 mm lateral and +14 mm axial displacements. [ABSTRACT FROM AUTHOR]

The evaluation of inductive coupling between coils of wire is a classic problem of electrical engineering. The accurate modeling of coupled coils has received renewed interest with the spread of wireless power transfer (WPT) systems. This problem has been quite well addressed for coplanar or perfectly coaxial coils but it is known the misalignment conditions easily lead to a sharp decrease of the efficiency. Hence, it is crucial to take misalignment into account in order to properly design the overall WPT system. The aim of this work is to develop an analytical procedure for the efficient calculation of the magnetic flux linkage between parallel flat pancake coils with lateral misalignment. The procedure consists of converting the original integral expression describing the flux into a sum of simpler finite integrals, which may be easily expressed in explicit form. Next, the flux linkage is given as a sum of elementary functions, that is as a combination of powers of geometrical parameters of the problem. The analytical method proves advantageous over numerical techniques in terms of computational speed, often reducing computation time significantly. For instance, analytical methods can achieve results in just a few milliseconds, as opposed to several seconds required by numerical methods like finite element analysis (FEA).

This paper presents the design and development of miniature coils for wireless power and data transfer through metal. Our coil has a total size of 15 mm × 13 mm × 6 mm. Experimental results demonstrate that we can harvest 440 mW through a 1 mm-thick aluminum plate. Aluminum and stainless-steel barriers of different thicknesses were used to characterize coil performance. Using a pair of the designed coils, we have developed a through-metal communication system to successfully transfer data through a 1 mm-thick aluminum plate. A maximum data rate of 100 bps was achieved using only harvested power. To the best of our knowledge, this is the first report that demonstrates power and data transfer through aluminum using miniature coils.

As neural implant technologies advance rapidly, a nuanced understanding of their powering mechanisms becomes indispensable, especially given the longterm biocompatibility risks like oxidative stress and inflammation, which can be aggravated by recurrent surgeries, including battery replacements. This review delves into a comprehensive analysis, starting with biocompatibility considerations for both energy storage units and transfer methods. The review focuses on four main mechanisms for powering neural implants: Electromagnetic, Acoustic, Optical, and Direct Connection to the Body. Among these, Electromagnetic Methods include techniques such as Near-Field Communication (RF). Acoustic methods using high-frequency ultrasound offer advantages in power transmission efficiency and multi-node interrogation capabilities. Optical methods, although still in early development, show promising energy transmission efficiencies using Near-Infrared (NIR) light while avoiding electromagnetic interference. Direct connections, while efficient, pose substantial safety risks, including infection and micromotion disturbances within neural tissue. The review employs key metrics such as specific absorption rate (SAR) and energy transfer efficiency for a nuanced evaluation of these methods. It also discusses recent innovations like the Sectored-Multi Ring Ultrasonic Transducer (S-MRUT), Stentrode, and Neural Dust. Ultimately, this review aims to help researchers, clinicians, and engineers better understand the challenges of and potentially create new solutions for powering neural implants. [ABSTRACT FROM AUTHOR]

The utilization of unmanned aerial vehicles (UAV) has become prevalent nowadays. UAVs are autonomous devices, except for self‐charging. Wireless power transfer (WPT) technologies eliminate human intervention in UAV charging and enable independent charging. The factors making WPT systems popular are autonomizing charging, eliminating cable complexity, and avoiding difficulties caused by environmental conditions. WPT of the UAV in the near field is provided by inductive coupling. In this paper, two vertical rectangular coils and horizontal DDD (triple rectangle) coils were placed in the receiver and the transmitter for UAV wireless charging, respectively. The design of the coils was made in ANSYS Maxwell 3D. A wireless charger of the UAV was designed for 100 W output power at 140 kHz frequency. The misalignment tolerance of the proposed design concerning the x‐ and y‐axis was examined. In addition, the magnetic flux density and magnetic field distributions of the WPT system were investigated. The study found that the proposed design can transfer energy wirelessly with 94% efficiency up to 10.3 cm horizontal and 1.7 cm vertical misalignment. [ABSTRACT FROM AUTHOR]

The frequent cable breaks and socket failures experienced by users of mobile devices such as smartphones and tablets have become a problem. In this study, wireless charging of mobile phones is provided with inductive coupling. The wireless power transfer (WPT) system has a diameter of 5 cm, operates at 10 MHz, and has an output power of 5 W. The coil design includes a ferrite core and shielding for reducing electromagnetic scattering. The paper used mathematical calculations and simulation tools, including MATLAB, Simulink, Maxwell 3D, and HFSS, to analyze the WPT design and its effects on human health at various conditions. As a result, the magnetic exposure was kept below the limit value in this WPT design, thus protecting the person and the device. In addition, the WPT design achieved high efficiency with a maximum air gap of 2 cm when aligned, and up to 2 cm misalignment at 0.5 cm air gap. [ABSTRACT FROM AUTHOR]

The harmonics and resonance of traction power supply systems (TPSSs) aggravate the electromagnetic interference (EMI) to adjacent metallic pipelines (MPs), which has aroused widespread concern. In this paper, an evaluation method on pipeline interference voltage under harmonic induction is presented. The results show that the Carson integral formula is more accurate in calculating the mutual impedance at higher frequencies. Then, an integrated train–network–pipeline model is established to estimate the influences of harmonic distortion and resonance on an MP. It is revealed that the higher the harmonic current distortion rate of the traction load, the larger the interference voltage on an MP. Particularly, the interference voltage is amplified up to 7 times when the TPSS resonates, which is worthy of attention. In addition, the parameters that affect the variation and sensitivity of the interference voltage are studied, namely, the pipeline coating material, locomotive position, and soil resistivity, indicating that soil resistivity and 3PE (3-layer polyethylene) anticorrosive coating are more sensitive to harmonic induction. Field test results show that the harmonic distortion can make the interference voltage more serious, and the protective measures are optimized. [ABSTRACT FROM AUTHOR]

Objective: To enhance RF safety when implantable medical devices are located within the body coil but outside the imaging region by using a secondary resonator (SR) to reduce electric fields, the corresponding specific absorption rate (SAR), and temperature change during MRI. Materials and methods: This study was conducted using numerical simulations with an American Society for Testing and Materials (ASTM) phantom and adult human models of Ella and Duke from Virtual Family Models, along with corresponding experimental results of temperature change obtained using the ASTM phantom. The circular SR was designed with an inner diameter of 150 mm and a width of 6 mm. Experimental measurements were carried out using a 3 T Medical Implant Test System (MITS) body coil, electromagnetic (EM) field mapping probes, and an ASTM phantom. Results: The magnitudes of B1+ (|B1+|) and SAR1g were reduced by 15.2% and 5.85% within the volume of interest (VoI) of an ASTM phantom, when a SR that generates opposing electromagnetic fields was utilized. Likewise, the Δ|B1+| and ΔSAR1g were reduced by up to 56.7% and 57.5% within the VoI of an Ella model containing a copper rod when an opposing SR was used. Conclusion: A novel method employing the designed SR, which generates opposing magnetic fields to partially shield a sample, has been proposed to mitigate the risk of induced-RF heating at the VoI through numerical simulations and corresponding experiments under various conditions at 3.0 T. [ABSTRACT FROM AUTHOR]

The idea of novel antennas and matching circuits, developed for radio frequency identification (RFID) passive transponders, and made on textile substrates, is presented in this paper. By manufacturing an RFID transponder by the means used in every clothing factory, we developed the concept of RFIDtex tags, which, as textronic devices, make a new significant contribution to the Internet of Textile Things (IoTT). The main feature of the device consists of the use of an uncommon inductively coupled system as the antenna feed element. The antenna is sewn/embroidered with a conductive thread, and the microelectronic module with an RFID chip is made in the form of a bead, using standard electronic technology. Finally, the construction of the RFIDtex tag is developed for easy implementation in production lines in the garment industry. The proposed inductive coupling scheme has not been considered anywhere, so far. The developed transponder is dedicated to operating in RFID systems of the ultra-high frequency band (UHF). The numerical calculations confirmed by the experimental results clearly indicate that the proposed coupling system between the antenna and the microelectronic module works properly and the RFIDtex device can operate correctly within a distance of several meters. The proposed design is based on the authors' patent on the textronic RFID transponder (patent no PL 231291 B1). [ABSTRACT FROM AUTHOR]

Signal‐to‐noise ratio (SNR) is one of the most common metrics in assessing the image quality of magnetic resonance imaging (MRI). Among a host of technological developments, various wireless devices, including metamaterials and volumetric wireless resonators have been reported to enhance SNR by redistributing the radio frequency magnetic field in the near field region. While theoretically feasible, their widespread clinical adoption has been limited by their field inhomogeneity, limited spatial coverage and challenges in their applications to higher field (≥3.0T) MRI systems. In this study, a Helmholtz coil‐inspired volumetric wireless resonator (HVWR) featuring a uniform magnetic field enhancement within the resonator volume is reported. The HVWR is free from cables, adapters and interface boxes, allowing for ease of fabrication and straightforward installation. The resonator allows for resonance frequency tunability and adaptivity, enabling for passive detuning during the MRI transmission phase. Experimental validation using a 3.0T MRI system demonstrate a substantial SNR boost (5× or higher) being achieved in a region covering the average size of the human knee. This study offers an efficient and practical wireless solution for improved MRI image quality that may be applicable across a range of imaging applications. [ABSTRACT FROM AUTHOR]

This paper presents a quasi-analytical method that allows the derivation of a rigorous series-form representation for the mutual inductance of two co-axial coil antennas located above an arbitrarily layered earth structure. Starting from Biot–Savart law, which gives the integral representation for the primary vector potential generated by the source coil, the potential reflected by the layered ground is derived, and the resulting total vector potential is then integrated along the external circumference of the receiving coil to give the mutual inductance of the two antennas. The obtained representation for the flux is then evaluated analytically through the usage of the Gegenbauer addition theorem once an accurate, rational approximation is used in place of the factor of the integrand that exhibits branch cuts. It is shown how the resulting explicit solution exhibits the same degree of accuracy as purely numerical approaches like the finite-difference time-domain (FDTD) method and conventional numerical quadrature schemes, while it is less time-demanding than the latter methods. [ABSTRACT FROM AUTHOR]

Nowadays, implanted permanent pacemakers (PPM) users need to undergo periodic pacemaker replacement surgery. The surgery is needed since the pacemaker's battery is usually depleted in 5-10 years. This surgery, although poses relatively low health risks, is inconvenient for PPM users. Moreover, the surgery can still be dangerous for PPM users, especially considering that most of the users are elderly. PPM replacement surgery is also costly. In addition to the costs of the surgery itself, the PPM users need to bear the price of the new PPM every time they undergo surgery. Currently, when the PPM's battery runs out, the whole PPM needs to be replaced. This is conducted to prevent the possibility of a leak in the battery seal, which might allow the body fluids to enter the PPM. Typically, once a battery is inserted into the PPM, it will be permanently sealed along with all other electronic components, and thus, battery-only replacement is impossible. Thanks to the recent advancement of wireless power transfer (WPT) technology, a PPM replacement surgery might no longer be necessary in the near future. This article presents a brief review of the current state of coil-based WPT technology and its potential applications in pacemakers. Depending on the load and transmission distance, a recent WPT system for PPM could achieve WPT efficiency as high as 97.91% on air and 78% on pig tissue medium. In terms of output power, recent works that we have summarized showed that they are able to transmit power up to 5W on a WPT system implemented on a human phantom. We also discuss the challenges, limitations, and future prospects for WPT in the medical field, particularly for PPM applications.

Abstract A simulation model composed of an interfering cable and a disturbed cable is established for studying the lightning inductive characteristics between parallel cables. Effects of the horizontal distance between cables (5–40 cm), their height difference (−6–32 cm), as well as the length of disturbed cable (1–100 m) are investigated for the cable induced voltage, which is measured at the resistive load connected between one terminal of the disturbed cable and the ground, when various lightning surge currents (8/20 μs, 5/320 μs, and 0.5 μs/100 kHz) are delivered into the interfering cable. Our findings show that an increase of horizontal distance between cables can give rise to an exponential decrease of the cable induced voltage, and that there exist linear correlations between either the height difference of two cables or the length of disturbed cable and the cable induced voltage, which reaches maximum when the cables are located at the same height and of equal length. Verification experiments for the effect of horizontal distance have also been made, and, in general, they all show a reasonable agreement with the simulations. A detailed theoretical explanation of obtained findings is provided as well.

Unmanned aerial vehicles (UAV) have been used in many fields nowadays. In long-term applications, batteries need to be constantly changed by someone due to short battery life. This problem is eliminated with wireless power transfer (WPT). A reliable, effective, and autonomous solution is offered using wireless charging. The most suitable wireless charging technique for UAVs is inductive power transfer (IPT). In this paper, a novel foldable coil and charge station design is proposed for the wireless charging of UAVs. IPT is provided by receiver and transmitter coils placed on the drone legs and the charging station, respectively. Receiver coils are placed on both legs of the UAV in a light and balanced manner to avoid creating imbalance and weight on the UAV. Receiver coils are designed as vertical rectangular planar spirals. A transmitter coil consists of three rectangular planar spiral coils with two movable edge windings and a fixed middle winding. The transmitter’s folding windings provide both alignments for the UAV during landing and increase the magnetic coupling. A folding wireless charge system of the UAV is designed for 100 W output power at a 138.1 kHz frequency. The misalignment tolerance of the proposed design in the vertical axis is examined. The design’s magnetic flux density distribution is analysed. As an experimental result of the study, 97.66% efficiency was reached in the aligned condition. Also, over 85.48% efficiency was achieved for up to 10 cm of vertical alignment misalignment.

As neural implant technologies advance rapidly, a nuanced understanding of their powering mechanisms becomes indispensable, especially given the long-term biocompatibility risks like oxidative stress and inflammation, which can be aggravated by recurrent surgeries, including battery replacements. This review delves into a comprehensive analysis, starting with biocompatibility considerations for both energy storage units and transfer methods. The review focuses on four main mechanisms for powering neural implants: Electromagnetic, Acoustic, Optical, and Direct Connection to the Body. Among these, Electromagnetic Methods include techniques such as Near-Field Communication (RF). Acoustic methods using high-frequency ultrasound offer advantages in power transmission efficiency and multi-node interrogation capabilities. Optical methods, although still in early development, show promising energy transmission efficiencies using Near-Infrared (NIR) light while avoiding electromagnetic interference. Direct connections, while efficient, pose substantial safety risks, including infection and micromotion disturbances within neural tissue. The review employs key metrics such as specific absorption rate (SAR) and energy transfer efficiency for a nuanced evaluation of these methods. It also discusses recent innovations like the Sectored-Multi Ring Ultrasonic Transducer (S-MRUT), Stentrode, and Neural Dust. Ultimately, this review aims to help researchers, clinicians, and engineers better understand the challenges of and potentially create new solutions for powering neural implants.

In this paper, an inductive wireless link for motion recognition is investigated. In order to validate the feasibility of a wearable implementation, the use of three different materials is analyzed: a thin copper wire, a conductive yarn, and a conductive non-woven fabric. Results from the application of the developed devices on an arm are reported and discussed. It is demonstrated that the proposed textile inductive resonant wireless links are well suited for developing a compact wearable system for joint flexion recognition. [ABSTRACT FROM AUTHOR]

The paper proposes is scheme of the self-sustaining resonant converter of the reactive into the active power. It includes a parallel resonant circuit and serial resonant circuit with inductively coupled with each other an auxiliary parallel circuit inductively coupled with each the first parallel circuit. The parallel circuits are excited by a different output elements of an input reactive power source (i. e. its inductance and capacitance). The auxiliary circuit excitates the current resonance in the parallel circuits i.e. the effect of the conditional “negative resistance”, thus evoidily the converter import on the reactive power source. The electromagnetic processes are analyzed using the well-known methods of the electric-circuit theory irrespective the resonant phenomena physics. The impact on the processes in the reactive-power source of a current maximum in the converter load is neglected. The calculated scheme element base parameters not only removing losses but even and increase the input power. [ABSTRACT FROM AUTHOR]

Human exploration of the ocean is inseparable from reliable ocean observation equipment. Wireless power transmission technology can supply power to the receiving end in a non-contact manner, saving complicated cable plugging and unplugging. Due to the conductivity of seawater, a certain amount of eddy current loss will be generated during wireless power transmission, reducing the output power and transmission efficiency. This paper designs a wireless power transmission system suitable for underwater scenes, and in this paper, the operational characteristics of the system are analyzed. At the same time, the transmission capability of the system in the air is studied, and the influence of several key parameters such as resonance frequency on the output power and transmission efficiency is analyzed. On this basis, combined with the calculation method of eddy current loss in seawater, the system transmission efficiency in seawater is calculated, which provides a reference for selecting the operating frequency. Finally, a coupler design scheme that is easy to dock with underwater devices and has a good electromagnetic shielding effect is given, and its transmission capability and performance under misalignment are analyzed through finite element simulation. According to the design plan, a prototype is built and experiments are carried out in air and simulated seawater environments. The experimental results verify the correctness of the theory. [ABSTRACT FROM AUTHOR]

The building block computation system is constructed by stacking various chips three-dimensionally. The stacked chips incorporate the same TCI IP (Through Chip Interface Intellectual Property) but cannot provide identical characteristics, requiring adjustments in power supply and bias voltage. However, providing characteristics measurement hardware for all chips is difficult due to the limitation of chip area or pin numbers. To address this problem, we developed TCI Tester, a small chip to measure electric characteristics by stacking on TCI of every chip. By stacking two TCI Tester chips, it appears that the up-directional data transfer has a stricter condition than down directional one on power supply voltage and operational frequency. Also, the transfer performance is poorer than designed. Similar measurement results are obtained by stacking TCI Tester on other chips with TCI IP. To investigate the reason, we analyzed the power grid resistance of various chips with the TCI IP. Results also showed that the chips with higher resistance have a narrow operational condition and poorer performance. The results suggest that the power grid design is important for keeping the performance through the TCI channel. [ABSTRACT FROM AUTHOR]

Abstract The harmonics and resonance of traction power supply systems (TPSSs) aggravate the electromagnetic interference (EMI) to adjacent metallic pipelines (MPs), which has aroused widespread concern. In this paper, an evaluation method on pipeline interference voltage under harmonic induction is presented. The results show that the Carson integral formula is more accurate in calculating the mutual impedance at higher frequencies. Then, an integrated train–network–pipeline model is established to estimate the influences of harmonic distortion and resonance on an MP. It is revealed that the higher the harmonic current distortion rate of the traction load, the larger the interference voltage on an MP. Particularly, the interference voltage is amplified up to 7 times when the TPSS resonates, which is worthy of attention. In addition, the parameters that affect the variation and sensitivity of the interference voltage are studied, namely, the pipeline coating material, locomotive position, and soil resistivity, indicating that soil resistivity and 3PE (3-layer polyethylene) anticorrosive coating are more sensitive to harmonic induction. Field test results show that the harmonic distortion can make the interference voltage more serious, and the protective measures are optimized.

The transmitting and receiving coils used in wireless power transfer (WPT) systems in electric vehicles (EVs) have a larger air gap (~300 mm) and higher transmission power (kW) than those in typical WPT systems used in electrical appliances. However, this could weaken the magnetic field, reduce transfer efficiency, and lead to a public concern regarding potential adverse health effects related to electromagnetic field (EMF) exposure. Therefore, the assessment of compliance with product safety standards, based on international exposure guidelines such as the International Commission on Non-Ionizing Radiation Protection (ICNIRP), is crucial. This study uses the finite element method to analyze a commonly used core-less and core-based WPT system using a composite core material in EVs and scalar potential finite difference method for assessment of human protection. Based on the computational results, two core structures using different types of intermediate insert blocks were analyzed to reduce external magnetic fields and mitigate the human EMF exposure. The WPT system with a core structure improved the transfer efficiency by 34% for a 300 mm air gap over the core-less system. Moreover, this effectively reduced magnetic field leakage by 91.6% and induced electric field by 98.3%, resulting in the reduction of induced electric field in anatomical human body model. The results demonstrated that a WPT system with a composite core can simultaneously improve the transfer efficiency and protect humans from EMF exposure.

Wireless Power Transfer (WPT) using inductive and magnetic resonance coupling developing at enormous pace due to its diversity of applications, such as electric vehicles (EV), biomedical implants, consumer electronics, robotics and so on. This review presents historical background together with applications of low power and high power WPT systems. The review emphasizes on two main design facets of WPT system including compensation networks and coil structure. All up-to-date compensation topologies are comprised in the review along with latest coil designs. Load-independent operation using compensation topologies is also reviewed. The review provides all available methods to analyze the circuit structure of WPT system theoretically and it also outlines the software used for circuit simulations as well as coil design. This paper is diverse from existing reviews in a pattern that it presents not only complete critical intuition on the vital design features, recent advancements, contemporary problems and challenges of low power and high power WPT systems but also provides the available theoretical methods as well as software to analyze the WPT system in wholesome. This paper will enrich the knowledge of the researchers to investigate the WPT systems using existing techniques and to solve the present-day design glitches of WPT systems.

This paper presents a design and optimization method utilizing inductive coupling coils for wireless power transfer in implantable neural recording microsystems, aiming at maximizing power transfer efficiency, which is essential for reducing externally transmitted power and ensuring biological tissue safety. The modeling of inductive coupling is simplified by combining semi-empirical formulations with theoretical models. By introducing the optimal resonant load transformation, the coil optimization is decoupled from an actual load impedance. The complete design optimization process of the coil parameters is given, which takes the maximum theoretical power transfer efficiency as the objective function. When the actual load changes, only the load transformation network needs to be updated instead of rerunning the entire optimization process. Planar spiral coils are designed to power neural recording implants given the challenges of limited implantable space, stringent low-profile restrictions, high-power transmission requirements and biocompatibility. The modeling calculation, electromagnetic simulation and measurement results are compared. The operating frequency of the designed inductive coupling is 13.56 MHz, the outer diameter of the implanted coil is 10 mm and the working distance between the external coil and the implanted coil is 10 mm. The measured power transfer efficiency is 70%, which is close to the maximum theoretical transfer efficiency of 71.9%, confirming the effectiveness of this method. [ABSTRACT FROM AUTHOR]

A simulation model composed of an interfering cable and a disturbed cable is established for studying the lightning inductive characteristics between parallel cables. Effects of the horizontal distance between cables (5–40 cm), their height difference (−6–32 cm), as well as the length of disturbed cable (1–100 m) are investigated for the cable induced voltage, which is measured at the resistive load connected between one terminal of the disturbed cable and the ground, when various lightning surge currents (8/20 μs, 5/320 μs, and 0.5 μs/100 kHz) are delivered into the interfering cable. Our findings show that an increase of horizontal distance between cables can give rise to an exponential decrease of the cable induced voltage, and that there exist linear correlations between either the height difference of two cables or the length of disturbed cable and the cable induced voltage, which reaches maximum when the cables are located at the same height and of equal length. Verification experiments for the effect of horizontal distance have also been made, and, in general, they all show a reasonable agreement with the simulations. A detailed theoretical explanation of obtained findings is provided as well. [ABSTRACT FROM AUTHOR]

This study focuses on using wireless power transfer (WPT) technology based on magnetic resonant coupling (MRC) to supply electric power to an endoscopic capsule to be used for the direct feeding of specific functions or for battery charging. One of the main limitations of the diffusion of endoscopic capsules is the limited autonomy of the internal battery. The aim of the paper is to present an innovative system to wirelessly power capsules using inductive coupling. Here, a new transmitting coil architecture is proposed to allow the wireless charging of the capsule equipped with a monoaxial receiving coil for any possible geometric position and orientation. The new wearable transmitting coil consists of four rectangular coils with independent excitations, and it is capable of producing a magnetic field in any direction. The obtained results in terms of electrical performance of the proposed WPT system and in terms of in situ electromagnetic physical quantities are compared with the basic restrictions of electromagnetic field (EMF) safety guidelines. The results obtained are very promising, as the proposed WPT configuration can transfer at least 250 mW in a capsule that travels along the entire gastrointestinal tract. [ABSTRACT FROM AUTHOR]

One of the greatest techniques, inductive coupling is frequently utilized in the biomedical sector for wireless energy transfer to implants. The aim of this article is to develop and analyze the effect of inductor geometrical characteristics, distance between transmitter (TX) and receiver (RX) and also the operating frequency on the wireless power transfer system, using grey wolf optimizer-based cuckoo search (GWO-CS) algorithm. Power transfer efficiency (PTE), power provided to load, and other critical components must all be improved or maximized and miniaturaze the microsystem proposed. The invention, design, and optimization of coils square spirals in a wireless energy transfer system using a resonant inductive link are the emphasis of this paper. The GWO-CS approach is evaluated to existing methods, demonstrated by simulations and to demonstrate the effectiveness of the suggested strategy. [ABSTRACT FROM AUTHOR]

In reaction to the depletion of resources, electric vehicles are viewed as an alternate choice. Wireless power transfer (WPT) is seen as a solution to charge batteries since practical and dependable ways to charge EV batteries are crucial for increasing the use of EVs in daily life. This project involves designing and implementing a wireless charger prototype with a 60 kHz operating frequency. The drawbacks of plug-in electric vehicles (PEV) include the requirement for a cable and plug charger, the need for galvanic isolation of the on-board electronics, the bulk and high cost of this charger, and the requirement for sizable energy storage system (ESS) packs. however, by utilizing the wireless charging capability of the equipment. It offers convenience to the user, built-in electrical isolation, grid-side regulation, and on-board ESS size reduction through dynamic on-road charging. The primary objective of our project is to design and construct an antenna system that can be used for vehicles to charge electric vehicles wirelessly using resonant magnetic resonance technology. WPT use in EVs offers a clean, practical, and secure functioning. Both the primary and secondary coils are the heart of the WPT systems. The coupling coefficient of the system created by these coils ranges from 0.1 to 0.5. Resonant capacitors are required on both sides to tune them in order to transmit the rated power. The operating frequency is a crucial selection factor for all applications, and it has a significant impact on the power electronic circuit's component choices and coil size. Vehicle charging technology is developed with a resonant wireless transfer system. [ABSTRACT FROM AUTHOR]

One of the major challenges associated with e-textiles is the connection between flexible fabric-integrated wires and rigid electronics. This work aims to increase the user experience and mechanical reliability of these connections by foregoing conventional galvanic connections in favor of inductively coupled coils. The new design allows for some movement between the electronics and the wires, and it relieves the mechanical strain. Two pairs of coupled coils continuously transmit power and bidirectional data across two air gaps of a few millimeters. A detailed analysis of this double inductive link and associated compensation network is presented, and the sensitivity of the network to changing conditions is explored. A proof of principle is built that demonstrates the system's ability to self-tune based on the current–voltage phase relation. A demonstration combining 8.5 kbit/s of data transfer with a power output of 62 mW DC is presented, and the hardware is shown to support data rates of up to 240 kbit/s. This is a significant improvement of the performance of previously presented designs. [ABSTRACT FROM AUTHOR]

Through inductive coupling, AC transmission lines can generate large amounts of voltage to buried oil and gas pipelines in areas with common corridors, posing a threat to the cathodic protection effect of pipelines. Therefore, this paper investigates the effect of AC transmission lines on the cathodic protection of long-distance pipelines through inductive coupling. COMSOL Multiphysics finite element simulation software is used to calculate the distribution of cathodic protection potential of long-distance pipelines under different voltage levels, parallel spacing, conductor-to-ground height, conductor arrangement and pipeline burial depth for normal operation of AC transmission lines. Comparison and analysis of the AC transmission line on the pipeline cathodic protection potential interference law is conducted. The results show that: 1. AC transmission lines cause serious electromagnetic interference with the pipeline cathodic protection system, which will cause the pipeline cathodic protection potential to shift out of the effective protection area. 2. The maximum value of the induced voltage of the pipeline will appear at the two ends of the pipeline, and the induced voltage of the pipeline in the middle position is 0. 3. The shift of the pipeline cathodic protection potential increases with the increase of voltage level and decreases with the increase of parallel spacing, conductor height and burial depth. The pipeline cathodic protection potential shift is highest when the wires are arranged horizontally and lowest when they are arranged in an umbrella shape. [ABSTRACT FROM AUTHOR]

Experimental campaigns were undertaken to understand and improve the coupling efficiency of Radio frequency (RF) power into the plasma in three accelerator-based ion sources. Different matching circuit and mechanical engineering setups were used and the network resistance calculated. The efficiency was then measured for a range of RF frequencies and input gas flows. Coupling efficiencies of around 60% were measured in setups using RF-coils mounted external to the plasma chamber. The efficiency is improved to 80% when the coil is immersed in the plasma, allowing closer coupling. As well as the coil geometry, the isolation transformer required for beam production contributes to the overall losses. [ABSTRACT FROM AUTHOR]

A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake (SP) insert no-insulation (NI) coil in a hybrid magnet during the charging and discharging processes. The coupled problem is resolved by means of the finite element method (FEM) for the magneto-thermo-elastic behaviors and the Runge-Kutta method for the transient responses of the electrical circuits of the hybrid superconducting magnet system. The results reveal that the transient multi-physics responses of the insert NI coil primarily depend on the charging/discharging procedure of the hybrid magnet. Moreover, a reverse azimuthal current and a compressive hoop stress are induced in the insert NI coil during the charging process, while a forward azimuthal current and a tensile hoop stress are observed during the discharging process. The induced voltages in the insert NI coil can drive the currents flowing across the radial turns where the contact resistance exists. Therefore, it brings forth significant Joule heat, causing a temperature rise and a uniform distribution of this heat in the coil turns. Accordingly, a thermally/mechanically unstable or quenching event may be encountered when a high operating current is flowing in the insert NI coil. It is numerically predicted that a quick charging will induce a compressive hoop stress which may bring a risk of buckling instability in the coil, while a discharging will not. The simulations provide an insight of hybrid superconducting magnets under transient start-up or shutdown phases which are inevitably encountered in practical applications. [ABSTRACT FROM AUTHOR]