In wireless power transfer (WPT) systems, the horizontal misalignment between coils and variations in the load result in significant fluctuations in the transmission efficiency of the system. In this paper, a reverse series triple coil (RTC) structure is proposed. The RTC structure offers improved resistance to deflection in the direction of vehicle motion because of the magnetic field interaction of the reverse series coils. This adjustment helps maintain a more stable system transmission efficiency when the coils are deflected. At the same time, when the load resistance varies within a certain range, the system's transmission efficiency remains almost unchanged. This is because the addition of relay coils makes the system more adaptable to load changes and improves the system's load compatibility. The experimental results indicate that the RTC structure corresponds to 300% of the load variation range of the conventional reverse series dual-coil structure, within the range where the system transmission efficiency is not less than 95%, in the load variation range that satisfies the load equivalent resistance from 15 Ω to 68 Ω. During the offset process, the maximum system transmission efficiency fluctuation rate is 1.19% for a distance of 55% of the core width of the offset transmitting coil on the horizontal Y-axis, and the maximum efficiency reaches as high as 97.26%.

This study investigates the effects of various antenna parameters, such as the substrate material, thickness of the superconducting patch, and operating temperature, on the resonance frequency and surface resistance/reactance of an H-shaped patch antenna printed on a uniaxial anisotropic substrate using a hybrid cavity model and fabricated with superconductor material. This model stands out for its simplified mathematical approach and cost effectiveness. Importantly, the numerical results demonstrate a high level of agreement with the experimental findings reported in the literature, reinforcing the reliability of our study. Additionally, other numerical results demonstrate the impact of the superconductivity materials on the resonant characteristics of the H-shaped compact microstrip antenna.

This paper proposes a cross-coupled filter that utilizes a coplanar waveguide (CPW) resonator and triangular substrate-integrated waveguide (TSIW) resonant cavities. The filter consists of a CPW resonator etched on the upper metal surface of a second-order triangular SIW resonant cavity. By adjusting the dimensions of the CPW resonator and optimizing the width of the inductive coupling window, precise control can be achieved over cross-coupling between resonators, enabling fine-tuning of both filter bandwidth and transmission zero placement. Simulation and test results indicate that the filter has a center frequency of 11.85 GHz, a -3 dB bandwidth of 1.82 GHz, a relative bandwidth of 15.4%, an insertion loss of -0.9 dB in the passband, a return loss of over 15 dB, and a transmission zero point located at 15 GHz. The filter has a simple structure, wide bandwidth, low insertion loss, small circuit size, and a flexible and controllable transmission zero point, making it potentially valuable for various applications.

An implicit causal space-time Galerkin scheme applied to the contrast current density volume integral equation gives rise to a marching-on-in-time scheme known as MOT-JVIE, which is accelerated and stabilized via a fully embedded FIR filter to compute the electromagnetic scattering from high permittivity dielectric objects discretized with over a million voxels. A review of two different acceleration approaches, previously developed for two-dimensional time-domain surface integral equations based on fast Fourier transforms (FFTs), leads to an understanding why these schemes obtain the same order of acceleration and the extension of this FFT-acceleration to a three-dimensional MOT-JVIE. The positive definite stability analysis (PDSA) for the MOT-JVIE shows that the number of voxels for a stable MOT-JVIE discretization is restricted by the finite precision of the matrix elements. The application of the PDSA provides the insight that stability can be enforced through regularization, at the cost of accuracy. To minimize the impact in accuracy, FIR-regularization is introduced, which is based on low group-delay linear-phase high-pass FIR-filters. We demonstrate the capabilities of the FFT-accelerated FIR-regularized MOT-JVIE for a number of numerical experiments with high permittivity dielectric scatterers.

A compact triple band antenna for wearable applications is presented in this paper. The antenna exhibits dual mode operation for ON/OFF body communication. The antenna has a patch like radiation pattern for OFF body communication and monopole like radiation pattern for ON body communication. Triple bands are achieved by incorporating an annular ring patch with the triangular patch. Tuning of the antenna and impedance matching has been done using two open ended rectangular slots and two shorting pins. As a result, the antenna has patch like radiation pattern at 2.5 GHz (ISM band), 3.5 GHz (Wi Max band) bands and monopole like radiation pattern at 5.5 GHz (WLAN band) band. The proposed antenna is compact in nature with a size of 70 × 70 × 2.1 mm³. User comfort has been taken into care with the use of all textile materials to fabricate the antenna except the SMA connector. A full ground plane in the proposed antenna ensures minimum coupling with human body and thereby a low SAR (specific absorption rate) value. Investigation of the antenna has been performed in both free space and on body scenarios.

In this paper, we propose a method for generating broadband orbital angular momentum (OAM) beams, utilizing the two neighboring ports of the uniform circular array (UCA) excited with a phase difference of (2(π+δ)l)/N. This approach differs from current arrays used to generate an OAM beam with a phase difference of 2πl/N. We establish that the UCA can produce OAM beams covering 83% (7-17 GHz) of the bandwidth. The array antenna consists of three Vivaldi elements with a phase difference between adjacent ports, capable of generating OAM beams of mode 2 when being fed with equal amplitude and phase. In contrast to current OAM antenna arrays that require complex phase-shifting networks for feeding, our proposed antenna array offers simplicity in its feeding mechanism. Furthermore, the UCA-based Vivaldi antenna presents a novel approach for generating wideband OAM beams and holds significant potential for applications in broadband communication.

The development of materials with excellent absorption properties in the C-band through the utilization of the magnetoelectric coupling effect holds great potential within the field of absorption research. However, there are still several challenges. To address these challenges, Fe@Carbon (Fe@C) microspheres were successfully fabricated using spray-drying followed by pyrolysis. The average size of the Fe@C microspheres is 3.6 µm with uniform dispersion, where iron nanoparticles (NPs) are tightly anchored with the carbon matrix to tune the microwave absorption properties. Synthesized Fe@C microspheres exhibit remarkable electromagnetic wave absorption capability within the C-band (4-8 GHz), covering a bandwidth of 2.8 GHz. Also, the Fe@C microsphere exhibits a minimum reflection loss of -48.11 dB at 4.5 mm thickness and 6.88 GHz. Systematic analysis has uncovered that the integration of large-sized magnetic carbon structures, high-density confinement of magnetic units, and robust magnetic coupling are crucial for enhancing the magnetic loss dissipation. This study introduces a novel approach for the preparation of electromagnetic absorbing materials, providing inspiration for further exploration of the mechanism behind low-frequency magnetic loss.

This article deals with the detection of defects of rectangular geometric shape, in a carbon fiber reinforced polymer (CFRP) composite material based on non-destructive testing by eddy current (ECT). For this, a stochastic finite element calculation code is developed in a Matlab environment. The main objective is to evaluate the ECT signal of a fault by determining the impedance variation for the two configurations, in the absence and presence of a fault. Additionally, the impact of the direction of the carbon fibers is exploited to evaluate the reliability of the material. The validation of our work is carried out using experimental data from the work of Takagi et al., provided for reference.

To address the insufficiency of large computation and unfixed switching frequency in permanent magnet synchronous motor (PMSM) of three-vector model predictive current control (TV-MPCC), simplified three-vector selection model predictive current control (STV-MPCC) for PMSM considering fixed switching frequency is proposed. Firstly, a novel voltage vector selection strategy is constructed by calculating the reference voltage in combination with the deadbeat control and re-dividing the sectors, reducing the number of optimizations from 11 to 5. Then, the current error is introduced in the calculation of the duty cycle to simplify the conventional control algorithm, The current ripple is reduced, and the system switching frequency is fixed. Finally, the experimental results indicate that compared with the conventional TV-MPCC, the d-q axis current ripple has been reduced by 13% and 18% respectively, and the torque ripple has been reduced by 6%, THD decreased from 4.70% to 4.25% and the steady-state performance of the motor is improved.

A compact UWB FSS reflector is presented based on an interdigital structure for gain enhancement of a UWB antenna. An equivalent circuit approach is proposed for the analysis of the FSS reflector. The reflector comprises a 6 × 6 array of unit cell dimension 6 mm × 6 mm and is very compact. The reflector gives a linear phase response over UWB. A UWB monopole antenna is designed with a half circular disc structure based on microstrip technology. A maximum of 5 dBi gain enhancement is achieved with this compact FSS reflector when it is placed at a distance below the antenna. The measured results closely follow the simulated ones which proves feasibility of this design.

This study introduces a groundbreaking circular ring-shaped fractal antenna optimized using particle swarm optimization (PSO) for wireless ultra-wideband (UWB) applications. The proposed fractal antenna design, featuring a central plus sign and an outer circular ring with eight smaller rings, enhances bandwidth for UWB response. The ground plane is modified with an etched curved slit to optimize antenna impedance. Utilizing PSO, we determine the fractal antenna's dimensions with optimization goals of minimizing size while ensuring |S₁₁| < -10 dB. Experimental data demonstrates strong performance across the 2.05 GHz-14.5 GHz frequency range, covering diverse wireless standards like UWB from 3.1 up to 10.6 GHz, X-band from 8 up to 12.5 GHz, and lower band of Ku from 12.5 to 14.5 GHz. Consistent measured and simulated results validate our contribution's applicability. Additionally, a time-domain analysis underscores the antenna's adaptability to UWB applications, offering insights into its response to transient signals.

Biomedical telemetry is, therefore, significant considering it facilitates prompt telecommunication as well as tracking of medical devices between centralized systems and patients. The availability and quality of communication of information are determined by the performance and selection of the telemetry antenna. This article analyzes the current state of BMA technology, aiming to extend the communication range and transmission speed of the data. The research article intends to contribute to the development of wireless technology. A plethora of antenna sizes are tackled from wearable to insertable antennas in addition to the improvements in materials and fabrication methods. The present review paper puts the thesis on only a few of the numerous biomedical telemetry antenna applications in healthcare, and these are the Internet of Medical Things (IoMT) and remote patient monitoring applications. it discusses case studies where better antennas had led to the creation of new therapeutic strategies, and diagnostic capacities, and had overall improved the quality of services. Therefore, the architectural problems of the existing designs are scrutinized, and this gives the other research areas the chance to be explored. A biological telemetry antenna is set to be the mobile edge computing solution that combines artificial intelligence, a 5G network, and edge computing. It also improves capital effectiveness over the transition period. Presentation makes it evident, why antennas are the essential component of the connected healthcare system and how antennas might redefine individualized care and the healthcare ecosystem. In conclusion, this research provides an extensive overview of the developments, uses, and future directions of biomedical telemetry antenna technology. It is an invaluable resource for academics, engineers, and medical professionals who seek to understand more about the evolving nature of this crucial component of modern healthcare systems.

In order to solve the problems of low reliability, low integration, and high cost brought by mechanical sensors in the control system of permanent magnet-assisted bearingless synchronous reluctance motor (PMa-BSynRM), a displacement self-sensing method of the Bback propagation (BP) neural network left-inverse system under the optimization of an improved particle swarm algorithm is proposed. Firstly, the working principle of PMa-BSynRM is introduced, and the mathematical model of PMa-BSynRM is derived. Secondly, the suspension force model is established to prove the left reversibility of the PMa-BSynRM displacement subsystem on the basis of the observation principle of the left reversible system. Thirdly, the weights of BP neural network are optimized by using the improved particle swarm algorithm to avoid local optimum, and the final weights are obtained to complete the construction of the displacement self-detection control system. On this basis, velocity change and anti-interference simulations are conducted to prove the tracking performance of the displacement system. Finally, static suspension, velocity change, and anti-interference experiments are executed which verify the accuracy and feasibility of the proposed displacement self-detection system.

In wireless communication systems, a control signal (CS) plays a vital role in managing the connection between transmitters (Txs) and the user equipment (UEs). This work presents CSs for non-orthogonal multiple access (NOMA)-based on visible light communication (VLC) systems. Moreover, pairing schemes, successive interference cancellation (SIC), and load balancing are considered with the NOMA-VLC technique for enhancing the entire performance. The CSs, which are single tones or can be described as unmodulated signals, are exploited to estimate the channel between Txs and UEs, and to evaluate the amount of interference at each UE. Thus, a controller, which is employed to manage the connections between Txs and UEs, can balance the load between Txs based on the level of interference at each UE. Each Tx is allocated a unique CS, i.e. a single-tone frequency. A power measurement unit (PMU) is utilized at each UE for measuring the power of each CS. Therefore, the controller divides the UEs into small groups based on the feedback signals from the PMU, then each group is connected to one Tx. Besides, CSs are used to find the optimum number of UEs that can be served by each Tx with a particular data rate of 50 Mbps and with an acceptable error probability of 10^-6, by utilizing on-off keying (OOK) modulation scheme.

5G wireless communication offers higher channel capacity, high data rate, sufficient bandwidth, enhanced coverage, and reliable link as compared to the previous generation mobile networks. Also, 5G becomes more relevant with the recent launches of low earth orbit satellites by various ventures like starlink, amazon, one web, etc. As these satellites have heights up to the range from 300 km to 1000 km, the free space path loss decreases drastically which in turn improves the signal reliability and efficient communication at dead spots. With these advancements, antenna researchers have the freedom to design compact, easy to manufacture, with adequate gain user equipment terminal antennas which can be easily integrated in the modern passenger car body. This paper will focus on the recent development in the design considerations of the compact antenna design at sub-6 GHz (n78 frequency band) and mm wave (n278 frequency band) according to 3gpp standards. This manuscript also discusses the various design specifications like selection of material for antennas, design complexity, feeding methods, fabrication and measurement challenges and performance parameters which include reflection coefficient, gain, polarization, axial ratio, cross polarization discrimination, radiation efficiency, radiation pattern shape, etc. The proposed antenna design considerations will facilitate the possible integration into the various parts of the car body according to the recent vehicular applications to uninterrupted communication.

The problem of unstable vibration signal and accurate fault feature extraction of motor bearing fault causes the low accuracy of motor bearing fault diagnosis. In order to improve the accuracy of motor bearing fault diagnosis, the variational mode decomposition (VMD) is used to decompose the vibration signal and combine with the convolutional neural network (CNN).The bearing faults are categorized into inner ring wear, outer ring wear and cage fracture; then each category of faults is further subdivided into the degree of loading, which is categorized into 0, 25% and 50%, with a total of 9 cases. In order to select sensitive fault features, the vibration signals of motor bearings in three dimensions are collected, decomposed into multiple endowment modal function (IMF) components by VMD. The energy entropy of each IMF in each dimension is extracted, and the sensitive fault features are selected by feature selection (ReliefF), and then input into CNN for fault diagnosis. At the same time, the fault diagnosis of transverse vibration signal and three-dimensional vibration signal is also carried out respectively. The experimental results show that the accuracy of the method is greatly improved, and the fault diagnosis can be realized.

Constant current (CC) charging and constant voltage (CV) charging are the two main charging stages of lithium-ion batteries in wireless charging systems. The traditional LCC-LCC topology has a high degree of design freedom. The conversion from CC to CV output is usually achieved through composite topology or frequency switching, which results in high control complexity and increases system cost. This paper proposes a wireless power transfer (WPT) system with CC and CV output characteristics based on topology reconstruction. Based on the LCC-LCC topology, by introducing one MOSFET in the rectifier and one AC switch which consists of two MOSFETs connected in reverse series to reconfigure the topology, the conversion from CC to CV mode can be achieved without complicated control methods and additional components. In addition, the proposed system works at a fixed operating frequency point, which can effectively avoid frequency bifurcation phenomenon. Therefore, the proposed system features a simple structure, easy control, low cost, and high robustness. In addition, ZPA operation can be realized in both CC and CV modes, ensuring high transmission efficiency. An experimental prototype with a rated power of 480W is built, and a maximum efficiency can reach 93.5%, which verifies the feasibility of the system.

The propagation study of electromagnetic (EM) waves within a human body is becoming essential due to the growing demand for the design and development of implantable sensing nodes in a body area network (BAN). Many researchers are interested in contributing to the development of propagation models in the ultra-wideband (UWB), i.e. 3.1 to 10.6 GHz, for biomedical applications, as well as the license-free Industrial, Scientific, and Medical (ISM) band. This kind of propagation model is essential in order to design and develop UWB transceivers for in-body, on-body, and off-body communications. This paper looks at the possibility of using a stepped slot patch antenna with a copper ground plane as either an off-body or on-body antenna by comparing measurements taken on a liquid human phantom. In addition, we use the empirical data to propose a statistical model.

This paper introduces a complementary split ring resonator (CSRR) patch antenna with elliptical slots on the ground plane for wireless communication, significantly amplified by placing two conducting elements over the substrate. The dimensions of the designed CSRR dual element multiple-input-multiple-output (MIMO) antenna are 16 x 32 mm² (0.66λ x 1.33λ). In this paper, the CSRR dual element MIMO antenna with an elliptical DGS resonates at 11.523 GHz, 12.305 GHz, and 15.178 GHz with reflection coefficients of -22.67 dB, -26.25 dB, and -47.65 dB respectively. It presents an impressive wide impedance bandwidth of 1.462 GHz covering 11.523 GHz and 12.305 GHz resonating frequencies and 1.446 GHz at 15.178 GHz resonance. The proposed design gives a gain of 5.29 dBi, 6.12 dBi, and 5.97 dBi for the resonating frequencies respectively. The results show a minimum envelope correlation coefficient (<0.025) and a significant diversity gain (>9.85) across the entire bandwidth. The measured results are close to the simulated ones, confirming the efficiency of the triple resonating frequencies with wideband, high-gain antenna design used for wireless communications for faster data transmission rates.

To improve the coupling problem between radial degrees of freedom in six-pole axial-radial active magnetic (AR-AMB), a decoupling control method based on an improved linear active disturbance rejection decoupling control strategy optimized by the least square support vector machine (LSSVM-ILADRC) is proposed. Firstly, the structure and working principle of the six-pole AR-AMB are introduced, and the mathematical model of suspension force is derived. Secondly, cascaded linear extended state observers (LESOs) are used to estimate the disturbance in degrees of freedom step by step, with LESO1 providing an initial estimate of the total disturbance, and LESO2 estimating and compensating for the difference between the initial estimate and the actual disturbance. The regression prediction function of LSSVM is employed to enhance the response speed and estimation accuracy of the LESO to the disturbance. Finally, the simulation and experimental research show that the proposed LSSVM-ILADRC decoupling control method has better decoupling performance and anti-interference performance than the ILADRC decoupling control method.