Vol. 143
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Vol. 143, 131-139, 2024
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A Miniaturized Double Sided Vivaldi Antenna with Enhanced Radiation Traits for Ew Applications
Mayank Vishwakarma , Puthalpattu Nagaraja Rao and Satyanarayana Vuta
This paper presents a compact double sided Ultra-Wideband (UWB) vivaldi antenna with corrugated structure. The proposed antenna is designed to operate from 5 GHz to 20 GHz frequency band. A comprehensive analysis of the antenna is carried out for its design, optimization, and performance especially for enhanced bandwidth and improved radiation characteristics. The antenna structure consists of vivaldi section which is printed on top and bottom layers of multi-layer printed circuit board (PCB) and fed with microstrip to strip lines transition. The antenna is fabricated and measured its return loss and radiation characteristics. The measured peak gain is 10.25 dBi at 17 GHz and return loss is better than -10 dB over the band 5 GHz to 20 GHz. Symmetrical radiation properties are observed over the band with excellent radiation characteristics especially in lower frequency bands as a result of comprised corrugated structure. Also, the far-field radiation pattern is symmetrical and directive throughout the operating band. The proposed design finds a suitable application in the field of an electronic warfare, precision ranging, microwave imaging.
A Miniaturized Double Sided Vivaldi Antenna with Enhanced Radiation Traits for EW Applications
Vol. 143, 121-129, 2024
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Machine Learning-Based Optimization of Hexagon-Shaped Fractal Antenna for Ultra-Wideband Communications
Sai Sampreeth Indharapu , Anthony N. Caruso , Travis D. Fields and Kalyan C. Durbhakula
In the wireless communication industry, achieving gigabit-per-second data rates with low-profile, ultra-wideband (UWB) microstrip patch antennae poses a significant challenge. Conventional optimization algorithms, though effective, are often computationally expensive, particularly for complex antenna geometries with high degrees of freedom. There is an imperative need for new methodologies to address this challenge and revolutionize the antenna optimization process. Successful and timely development of antennas relies on the efficiency and computational speed of optimization algorithms, full-wave electromagnetic (EM) solvers, and the intuition of radio frequency engineers. To mitigate the dependence on complex and time-consuming processes, we propose an efficient machine learning (ML)-based antenna optimization methodology that minimizes optimization time by more than 90%. This paper aims to apply and study the performance of two specific ML models, the radial basis function (RBF) and the least squared regression (LSR) models, in the bandwidth optimization without increasing the aperture area of a hexagon-shaped fractal antenna. The hexagon-shaped fractal antenna was chosen for its UWB characteristics, low profile, and high degrees of freedom (10 adjustable parameters). The reflection coefficient response of a hexagon-shaped fractal antenna is predicted by the trained RBF and LSR models and further optimized by the genetic algorithm (GA). The proposed approach stands out among other notable works in this research domain, especially for ultrawideband (UWB) applications, by prioritizing the optimization of the mean of |S11| across the entire frequency range instead of solely targeting individual frequency points. The GA-based optimization using trained ML models has increased the bandwidth by 30.20% and reduced the computational time by 90% compared to conventional optimization without increasing the physical or electrical size of the antenna. Simulation and measurement results concurred with a maximum difference of 5%, demonstrating the efficacy of the ML approach for antenna optimization.
Machine Learning-based Optimization of Hexagon-shaped Fractal Antenna for Ultra-wideband Communications
Vol. 143, 109-119, 2024
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Simulation Study of Digital Spatial Processing in Conditions of Tropospheric Propagation of Radio Waves for Telecommunication Applications
Ilia Peshkov
In this paper, the propagation of electromagnetic rays in a tropospheric waveguide and spatial processing using digital antenna arrays are studied. The beam traveling through the layers of the atmosphere depends on the refractive index and its vertical change. In this regard, conditions may arise when radio rays propagate in a waveguide manner at low altitudes. In this case, attenuation takes place, and the effect of multipath fading may also occur, when several rays reflected from different layers of the troposphere and with various spatial coordinates in elevation arrive at the receiver. It is proposed to apply digital antenna arrays to increase the range and reliability of radio communication through the tropospheric waveguide. Parabolic equations are utilized to estimate the path loses of radio waves of the centimeter wavelength. A ray-tracing algorithm via a tropospheric waveguide is used to estimate the mutual phases in the aperture of the receiving array. Bit error rate curves were obtained depending on the geometry of the antenna arrays after the signal passed through the tropospheric waveguide.
Simulation Study of Digital Spatial Processing in Conditions of Tropospheric Propagation of Radio Waves for Telecommunication Applications
Vol. 143, 99-107, 2024
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Research on Induced Electrical Characteristics of Agricultural Machinery Operating Under Ultra High Voltage ac Transmission Lines in Agricultural Area
Bin Hu , Meng Zhang , Xiaohe Zhao , Bingchen Hou and Zhongqing He
In plain areas, the majority of the ultra-high voltage(UHV) transmission corridors are located in farmland. The induced voltage is generated on the metal casing of the machinery when agricultural machines are working on the ground near the transmission line. If the human body touches, transient electric shock(TES) may occur, causing displeasure and alarm to workers. Therefore, it is crucial to study the induced electrical characteristics in such scenarios. In this article, the finite element method (FEM) was employed to establish a model integrating a 1000 kV transmission line, tractor, and human body, and the induced voltage of the tractor and human body under the transmission line was calculated. Subsequently, a TES model was developed to calculate the current when an electric shock occurs. Finally, an experimental system was constructed in the area beneath the 1000 kV UHV AC line to measure the current characteristics of the human body during the TES. The results demonstrate that the induced voltage is contingent upon the position of research object and whether it is insulated from the ground. Additionally, ground conditions significantly influence the TES current induced by the voltage. Due to the electromagnetic shielding effect of the tractor's metal casing, the TES current experienced by the driver inside the machine is minimized. For ground staff, when the human body is insulated from the ground, the transient electric shock current they bear is smaller than that of the human body grounded.
Research on Induced Electrical Characteristics of Agricultural Machinery Operating under Ultra High Voltage AC Transmission Lines in Agricultural Area
Vol. 143, 87-98, 2024
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Wireless Power Transfer System for Cardiac Pacemakers Based on Multi-Coil Series Magnetic Integration
Xiaoheng Yan , Jinshu Yao , Weihua Chen and Yuhang Song
We proposed a wireless power transfer system for cardiac pacemakers utilizing a multi-coil series magnetic integrated inductor-capacitor-capacitor/none (LCC-N) circuit topology operating at 50 kHz to reduce the volume of wireless power transfer systems for implanted pacemakers. Firstly, we established a mathematical model of LCC-N compensation topology and analyzed the relationship between the mutual inductance of the compensation and receiving coil and the system's transmission efficiency. The conclusion that the anti-offset performance of the system can be improved by using the change of the mutual inductance value was obtained. Secondly, the optimal coil structure was obtained via parameterized scanning, and a wireless power transfer system model for LCC-N was established for finite element simulation. The comparison of magnetic field strength was made between integrated and traditional non-integrated structures under aligned and offset conditions. Finally, the finite element simulation software ANSYS was adopted to establish a human body model, analyze the electromagnetic interference of the system to the human body, and evaluate the system's safety. Experimental results validated that the transmission efficiency of the system can reach 68.37%, and the output power was 1.47 W under multi-coil series magnetic integrated structure when the transmission distance was 8 mm. The transmission efficiency remained 57.87% even with a horizontal offset of 8 mm, which is 13% higher than the traditional non-integrated structure.
Wireless Power Transfer System for Cardiac Pacemakers Based on Multi-coil Series Magnetic Integration
Vol. 143, 75-86, 2024
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Mutual Inductance Calculation Method of Rectangular Coils with Bilateral Bounded Single-Hole Type Magnetic Medium in Wireless Power Transfer Systems
Lingjun Kong , Zhongbang Chen , Changxuan Hu , Chenxi Zhang , Jianbin Wang , Xin Zhou , Lin Jia and Zhongqi Li
The mutual inductance between the transmitting and receiving coils is one of the critical parameters of the wireless power transfer system, and an accurate mutual inductance calculation method can provide a reliable theoretical basis for the optimization of the coil structure of the wireless power transfer system. The addition of magnetic medium materials on both sides of the rectangular coil can effectively increase the mutual inductance, but there is no study on the mutual inductance calculation method for a rectangular coil with a bilateral bounded single-hole type magnetic medium. In this paper, the space vector domain synthesis method is proposed to solve the analytical value of mutual inductance, which solves Poisson's and Laplace's equations by separating the variables to obtain the magnetic vector potential in each region, and combines with the magnetic field boundary conditions to obtain the mutual inductance calculation formula by utilizing different dimensional vector syntheses. An experimental set of wireless power transfer systems with bilateral bounded single-hole type magnetic medium rectangular coils is also constructed, and the maximum error of the mutual inductance calculation value, experimental value, and simulation value is 5.82%, which verifies the effectiveness of the method proposed in this paper. The model proposed in this paper saves 5.86% of the material compared with the rectangular magnetic medium structure under the same parameters, and the mutual inductance is up to 99% of the rectangular magnetic medium structure.
Mutual Inductance Calculation Method of Rectangular Coils with Bilateral Bounded Single-hole Type Magnetic Medium in Wireless Power Transfer Systems
Vol. 143, 67-74, 2024
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High Isolated Defected Ground Structure Based Elliptical Shape Dual Element MIMO Antenna for S-Band Applications
Praveen Kumar , Ajit Kumar Singh , Ranjeet Kumar , Rashmi Sinha , Santosh Kumar Mahto , Arvind Choubey and Ahmed Jamal Abdullah Al-Gburi
This research suggests a compact, wideband Multiple Input Multiple Output (MIMO) antenna designed for S-band applications, emphasizing high isolation between closely positioned antenna elements. Achieving this isolation is accomplished through the implementation of a Defected Ground Structure (DGS) technique. The DGS is realized by etching two elliptical patterns on an economical FR-4 substrate with inherent loss properties. Three rectangular slots and two L-shaped stubs are introduced to improve isolation and minimize the size of antenna increment by lowering surface wave propagation. To validate the proposed layout, a physical prototype was constructed for a direct comparison of its performance with the simulated parameters. The results demonstrated highly favorable outcomes, including Diversity Gain (DG) exceeding 9.97 dB, Envelope Correlation Coefficient (ECC) registering below 0.05, Mean Effective Gain (MEG) lower than -3 dB, Total Active Reflection Coefficient (TARC) below 0.4, and Channel Capacity Loss (CCL) less than 0.3. Furthermore, the current distribution and radiation pattern were found to be highly suitable for applications in the S-band and the lower part of the C-band, encompassing technologies like Bluetooth, WiFi, WiMAX, 4G, and 5G.
High Isolated Defected Ground Structure Based Elliptical Shape Dual Element MIMO Antenna for S-band Applications
Vol. 143, 57-66, 2024
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A Compact Four Port High-Isolation SIW-Backed Self-Quadruplexing Antenna with a Swastik Shaped Slot for C Band Applications
Anil Kumar Katta and Praveen Babu Choppala
A compact planar self-quadruplexing antenna backed with the SIW technology with high isolation between the input ports is designed and demonstrated for the simultaneous quad-band operation of the antenna. The SIW cavity is integrated with a Swastik shaped slot and two metallic vias to generate four distinct frequency bands with high gain and low cross polarization. Utilizing four distinct orthogonal patches with different lengths, each independently connected to a 50-Ω microstrip feed line, makes the antenna operate at four frequency bands of 4.8, 5.5, 6.6, and 7.6 GHz. The minimum value of Front-To-Back-Ratio (FTBR) is 18 dB, and the minimum isolation between the input ports is 28.4 dB. The measured values of peak gains in the frequency bands 4.8, 5.5, 6.6 and 7.6 GHz are 5.05, 6.20, 6.45 and 6.32 dBi, respectively. Hence, a single antenna consists of four signals transmitting or receiving simultaneously from four individual input ports without interfering with each other and with high isolation between the input ports confirms the self-quadruplexing property of the antenna. This antenna configuration enables the independent tuning of each resonant frequency according to specific application needs by manipulating a single parameter, that is the length of the patch and without disturbing other performance parameters of the antenna. To validate the simulation results, the antenna is fabricated and tested. The measurement findings match the simulation results closely, which confirms the quad-band operation of the antenna design. Simple configuration, compact size, high gain, and low cross polarization of the antenna make the proposed planar antenna suitable for practical multiband applications and for handheld transceivers with high isolation between the input ports.
A Compact Four Port High-isolation SIW-backed Self-quadruplexing Antenna with a Swastik Shaped Slot for C Band Applications
Vol. 143, 45-56, 2024
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Design and Evaluation of 5-DOF Magnetic Bearing System for Saucer-Shaped Flywheel Battery
Weiyu Zhang , An Li and Jingwen Wang
In this study, a novel vehicle-mounted flywheel battery system is proposed, which can effectively balance the load capacity with margin, strong anti-interference, uncoupled magnetic circuit and low energy consumption. The proposed new flywheel battery adopts multiple magnetic circuits, reducing the number of permanent magnets and the complexity of the magnetic circuit. It is worth mentioning that the proposed ``side branch'' radial/tilting shared magnetic circuit can realize the main bearing function of the flywheel weight, and the axial biased magnetic field is used to suspend the near ``zero weight'' flywheel, so that the flywheel can withstand a certain interference margin in the axial direction, and then improve the active disturbance rejection and effectively reduce the control loss. After optimization, the unique overall structure of the flywheel battery can significantly improve the overall performance of the flywheel battery. Finally, the stiffness, decoupling, and anti-interference experiments are carried out, and the experimental results show that the proposed flywheel battery has good performance.
Design and Evaluation of 5-DOF Magnetic Bearing System for Saucer-shaped Flywheel Battery
Vol. 143, 35-43, 2024
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Research on Electromagnetic Vibration and Noise Suppression of PMaSynRM with Slotted Stator and Rotor
Zhentian Zhu , Aiyuan Wang and Ming Tang
Permanent magnet assisted synchronous reluctance motor (PMaSynRM) has been widely concerned, but the research on the vibration and noise of this kind of motor is relatively limited. In addressing the problem of significant vibration noise caused by radial electromagnetic force waves in PMaSynRM. The research explores a motor vibration and noise suppression solution involving stator slotting and rotor magnetic isolation hole opening. The study analyzed the impact of different slotting parameters on the radial electromagnetic force and air gap magnetic flux density of the motor and compared it with the solution involving slotting of the stator teeth only and magnetic isolation hole opening of the rotor only. Finally, the modal, vibration response and noise response of the motor after slotting are analyzed and verified. The results show that the amplitude of radial electromagnetic force and the total harmonic distortion rate of the air gap magnetic flux density of the motor are significantly reduced by opening the stator auxiliary slot and the rotor magnetic isolation hole. The maximum vibration acceleration of the motor is reduced by 33.44 mm/s2, and the peak A-weighted sound pressure level of the motor decreases by 5.49 dBA.
Research on Electromagnetic Vibration and Noise Suppression of PMaSynRM with Slotted Stator and Rotor
Vol. 143, 23-33, 2024
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Reconfigurable Designs of Sectoral Microstrip Antennas for Wideband and Circularly Polarized Response
Venkata A. P. Chavali , Amit A. Deshmukh , Aarti G. Ambekar , Hari Vasudevan and Tushar V. Sawant
Gap-coupled designs of Sectoral microstrip antenna for 90˚ and 45˚ sectoral angle are proposed for wideband and circularly polarized response. On total substrate thickness of ~0.1 g, proximity fed design of 90˚ Sectoral patch yields simulated bandwidth of 827 MHz (50.41%) with a peak gain of 8.1 dBi, whereas its gap-coupled configuration with parasitic 45˚ Sectoral patches yields simulated bandwidth of 1336 MHz (69.11%) with a peak gain of 8.0 dBi. A gap-coupled design of two 90˚ Sectoral patches is presented in which orthogonal directions of the fundamental mode currents over the aperture are maintained. This yields circularly polarized response with axial ratio bandwidth of 709 MHz (34.88%), which lies inside the impedance bandwidth of 1103 MHz (60.09%). It offers a peak gain of larger than 7 dBi across the axial ratio bandwidth. To achieve all these operational features using a single patch, a reconfigurable design of Sectoral patches is proposed that yields similar wideband and circularly polarized characteristics. Thus, present study provides a wideband and circularly polarized design that offers either impedance bandwidth of more than 65% or axial ratio bandwidth of nearly 35%. For achieved antenna response, the proposed designs fulfill the requirements of LTE (band 65, 66, and 70) and various aeronautical service mobile satellite bands (1610-2300 MHz). Experimental validation for the obtained results is carried out that shows close matching.
Reconfigurable Designs of Sectoral Microstrip Antennas for Wideband and Circularly Polarized Response
Vol. 143, 11-21, 2024
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Human Motion Recognition Based on Feature Fusion and Transfer Learning
Xiaoyu Luo and Qiusheng Li
In order to solve the problem that the recognition accuracy of human motion is not high when a single feature is used, a feature fusion human motion recognition method based on Frequency Modulated Continuous Wave (FMCW) radar is proposed. By preprocessing the FMCW radar echo data, the range and Doppler parameters of human motions are obtained, and the range-time feature map and Doppler-time feature map datasets are constructed. In order to fully extract and accurately identify the human motion features, the two features are fused, and then the two features maps and feature fusion spectrograms are put into the VGG16 network model based on transfer learning for identification and classification. Experimental results show that this method can effectively solve the problem of lack of information and recognition rate of single feature motion recognition, and the recognition accuracy is more than 1{\%} higher than that of the single feature recognition method.
Human Motion Recognition Based on Feature Fusion and Transfer Learning
Vol. 143, 1-10, 2024
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Harmonic Closed-Loop Model Combined Predictive Fault-Tolerant Control of Double Parallel Rotor Permanent Magnet Synchronous Motor
Hai Pu
Double Parallel Rotor Permanent Magnet Synchronous Motors exhibit superior performance and compact size, but the growing trend of electrification imposes higher demands on them. This study proposes a predictive fault-tolerant control integrating a closed-loop identification model and conducts experiments on Double Parallel Rotor Permanent Magnet Synchronous Motors. Results indicated that the proposed closed-loop identification model, along with its fractional-order lead-lag compensator module, effectively optimized motor performance, reducing average tracking error by 78.36%. Additionally, with demagnetization faults, the predictive fault-tolerant control outperformed traditional fault-tolerant control in speed, current, and torque fault-tolerant control, demonstrating superior performance. Through 10 weeks of practical application records, Double Parallel Rotor Permanent Magnet Synchronous Motors achieved a working accuracy of 95%-99% under the closed-loop identification model, with recall rates reaching 92%-96% in fault-tolerant scenarios. In both natural and simulated demagnetization fault situations, 97.69% of Double Parallel Rotor Permanent Magnet Synchronous Motors could continue normal operation. This research holds positive significance for the development of motor systems and enhancing their adaptability in the trend of electrification.
Harmonic Closed-loop Model Combined Predictive Fault-tolerant Control of Double Parallel Rotor Permanent Magnet Synchronous Motor