Enhanced transmission efficiency of magneto-inductive wave propagating in non-homogeneous 2-D magnetic metamaterial array

2022 ◽  
Author(s):  
Thi Hong Hiep Le ◽  
Thanh Son Pham ◽  
Bui Xuan Khuyen ◽  
Bui Son Tung ◽  
Quang Minh Ngo ◽  
...  
Keyword(s):  
Near Field ◽  
Low Frequency ◽  
Transmission Efficiency ◽  
Position Sensor ◽  
Wireless Power ◽  
Current Ratio ◽  
Enhanced Transmission ◽  
Unit Cells ◽  
Simulation And Experiment ◽  
Ratio Transmission

Abstract In this work, we investigate the propagation of magneto-inductive waves (MIWs) in ordering magnetic metamaterial (MM) structures. The proposed non-homogeneous MM slab consists of 9 × 9 MM unit cells constructed from a five-turn spiral embedded on an FR-4 substrate. External capacitors with the value of 40 pF or 50 pF were added to control the resonant frequency of each unit cell in accordance with the waveguide configurations. The characteristics of metamaterial structures, such as negative permeability, current ratio, transmission response, and field distribution in the waveguide, have been thoroughly analyzed by simulation and experiment. Because of the strong magnetic field confinement in the waveguide, the transmittance after nine elements of the non-homogeneous MM slab is 5.2 times greater than that of the homogeneous MM slab. This structure can be applied to the planar near-field wireless power transfer, position sensor, and low-frequency communication.

Analysis on space transmission model of the Microwave Wireless Power Transfer system

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Cheng Peng ◽  
Zhi-Hao Ye ◽  
Yi-Hui Xia ◽  
Chao Yang
Keyword(s):  
Near Field ◽  
Wireless Power Transfer ◽  
Transmission Efficiency ◽  
Transmission Model ◽  
Engineering Practice ◽  
Power Transfer ◽  
Wireless Power ◽  
Wireless Power Transfer System ◽  
Field Area ◽  
Transmission Models

Abstract This paper systematically analyzes the main link that imposes restrictions on the overall efficiency of the Microwave Wireless Power Transfer (MWPT) system–space transmission. Three typical transmission models of aperture transmission in the near-field area, radiation-focused transmission in the middle-field area, and Friis transmission in the far-field area of radiation were analyzed and calculated. Then, the applicable conditions and efficiency of three-models were compared. And the influence of antenna electrical parameters on the efficiency of the MWPT system was discussed. In the end, three typical space transmission models of aerial vehicles, satellites, and islands were studied. The influence of the medium on the transmission efficiency was emphatically analyzed. This paper aims to summarize the general laws of space transmission of microwave energy. Provide a theoretical reference for related scientific research and engineering practice.

scholarly journals Textile-Based Coils for Inductive Wireless Power Transmission

2021 ◽  
Vol 11 (9) ◽  
pp. 4309
Author(s):  
Sebastian Micus ◽  
Laura Padani ◽  
Michael Haupt ◽  
Götz T. Gresser
Keyword(s):  
Electromagnetic Induction ◽  
Power Transmission ◽  
Near Field ◽  
Electrical Energy ◽  
Transmission Efficiency ◽  
Maximum Efficiency ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
Conductive Materials ◽  
Transmission Quality

We developed and evaluated different textile-based inductive coils for near-field wireless power transmission. The technology uses electromagnetic induction for the contactless transfer of electrical energy. Therefore, we investigated various methods for the attachment of conductive materials on a textile-based material and the production of textile-based coils based on QI standard. Afterwards, the textile-based coils were examined and evaluated due to their specific quality characteristics. This happens by calculating the transmission quality and the maximum efficiency of the system which enables comparison of different coil systems and indicates the transmission efficiency of the systems.

Experimentally validated model and analytical investigations on power optimization for piezoelectric-based wireless power transfer systems

2019 ◽  
Vol 30 (16) ◽  
pp. 2464-2477 ◽  
Author(s):  
Binh Duc Truong ◽  
Shane Williams ◽  
Shad Roundy
Keyword(s):  
Power Optimization ◽  
Near Field ◽  
Equivalent Circuit Model ◽  
Low Frequency ◽  
Wireless Power Transfer ◽  
Electrical Energy ◽  
Power Transfer ◽  
Wireless Power ◽  
Lumped Model ◽  
Tip Mass

This article presents a near-field low-frequency wireless power transfer system utilizing a piezoelectric transducer with magnet tip mass as a receiver. The interaction moment between the uniform B field generated by a Helmholtz coil and the magnet is the means to deliver the electrical energy from the transmitter to an electrical load, which is therefore referred to as magneto-mechano-electric effect. This is the first time a complete equivalent circuit model of such a structure is developed and experimentally verified. Based on the lumped model, various aspects of the power optimization problem are thoroughly discussed, providing a comprehensive view of the system and an important premise for further study.

COUPLING-BASED TURNS DISTRIBUTION FOR PLANAR SPIRAL COIL ANTENNAS IN NEAR FIELD MAGNETIC INDUCTION LINKS

2015 ◽  
Vol 77 (10) ◽  
Author(s):  
Akaa Agbaeze Eteng ◽  
Sharul Kamal Abdul Rahim ◽  
Chee Yen Leow ◽  
Beng Wah Chew
Keyword(s):  
Numerical Study ◽  
Near Field ◽  
Transmission Efficiency ◽  
Power Delivery ◽  
Q Factor ◽  
Wireless Power ◽  
Transmission Performance ◽  
Spiral Coil ◽  
Efficiency Performance ◽  
Coil Antenna

This paper describes a numerical study of a coupling-based turn-distribution approach to achieving good transmission performance in near field magnetic inductive links using low Q-factor coil antennas. Coil antenna turns are distributed to match an upper reference coupling level, leading to a stronger axial H-field, with a low margin of Q-factor increment from a baseline minimum. Numerical results demonstrate improved transmission efficiency performance relative to a minimal Q-factor coil antenna when the modified antenna is employed in a symmetric bi-directional inductive link.  This approach to increasing transmission efficiency indicates prospects for extending the utility of low Q-factor HF-RFID interrogator antennas to include wireless power delivery applications.  

scholarly journals Practical Model for Metamaterials in Wireless Power Transfer Systems

2020 ◽  
Vol 10 (23) ◽  
pp. 8506
Author(s):  
Jingying Liu ◽  
Zhi Gong ◽  
Shiyou Yang ◽  
Hui Sun ◽  
Jing Zhou
Keyword(s):  
Resonance Frequency ◽  
High Frequency ◽  
Near Field ◽  
Low Frequency ◽  
Wireless Power Transfer ◽  
System Efficiency ◽  
Power Transfer ◽  
Wireless Power ◽  
Electric Circuits ◽  
Practical Model

Metamaterials (MTMs) with extraordinary electromagnetic properties are recently applied to wireless power transfer (WPT) systems to improve power transmission efficiency. Although theoretical progress has been made on MTMs in low frequency near field, in the operation frequency of most WPT systems (usually MHz), the design of MTMs still utilizes the model used in high-frequency applications. Therefore, a practical model of MTMs in low MHz band is proposed in this work. The resonance frequency and quality factor are used to describe the characteristics of an MTM slab. The near field WPT systems with MTMs are then modeled as electric circuits, the system efficiency is explicitly deduced, and optimization algorithms are employed to optimize the MTM resonance frequency and maximize the system efficiency. The proposed practical model is validated via a prototype wireless power transfer system operating at 6.78 MHz. Experiments show that the proposed MTM model has good accuracy for low MHz WPT systems compared with the high-frequency model. The proposed practical model of MTMs provides an accurate way to analyze the performance of MTM at low MHz frequencies and greatly benefits the future exploitation of MTM-based low-frequency near field applications.

Compensating Resonant Frequency via Adjusting Adjustable Coil Automatically

2019 ◽  
Vol 12 (5) ◽  
pp. 432-438
Author(s):  
Jin Xu ◽  
Yuting Zhao
Keyword(s):  
Resonant Frequency ◽  
Power Transmission ◽  
Reference Value ◽  
Transmission Efficiency ◽  
Theoretical Research ◽  
Future Research ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
Resonant Coupling ◽  
Transmission Distance

Background: Detuning is the main problem that affects the efficiency and transmission distance of the resonant coupling Wireless Power Transmission (WPT). The distance of load and the offset of the load position could cause serious detuning. Methods: This paper presents an adjustable coil in which inductance can be adjusted. Then a model of WPT was established that could compensate resonant frequency automatically using the adjustable coil. Next, the relationship between the primary resonant frequency and the transmission efficiency is analyzed from the circuit. The analysis proved that the design of the adjustable coil could improve the transmission efficiency of the WPT system. Finally, a prototype of WPT system was built. Results: The experimental results showed that WPT system with adjustable coil can improve the transmission efficiency which proves the theoretical research. At the same time, it has essential reference value for the future research of WPT. Conclusion: In this paper, aiming at the system detuning caused by some other factors, such as the position shift of the load during the wireless power transmission, an adjustable coil is proposed.

scholarly journals Occluded Grape Cluster Detection and Vine Canopy Visualisation Using an Ultrasonic Phased Array

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2182
Author(s):  
Baden Parr ◽  
Mathew Legg ◽  
Stuart Bradley ◽  
Fakhrul Alam
Keyword(s):  
Near Field ◽  
Low Frequency ◽  
Volume Estimation ◽  
Yield Estimation ◽  
3D Scan ◽  
Management Processes ◽  
Canopy Volume ◽  
Ultrasonic Phased Array ◽  
Added Benefit ◽  
Grape Yield

Grape yield estimation has traditionally been performed using manual techniques. However, these tend to be labour intensive and can be inaccurate. Computer vision techniques have therefore been developed for automated grape yield estimation. However, errors occur when grapes are occluded by leaves, other bunches, etc. Synthetic aperture radar has been investigated to allow imaging through leaves to detect occluded grapes. However, such equipment can be expensive. This paper investigates the potential for using ultrasound to image through leaves and identify occluded grapes. A highly directional low frequency ultrasonic array composed of ultrasonic air-coupled transducers and microphones is used to image grapes through leaves. A fan is used to help differentiate between ultrasonic reflections from grapes and leaves. Improved resolution and detail are achieved with chirp excitation waveforms and near-field focusing of the array. The overestimation in grape volume estimation using ultrasound reduced from 222% to 112% compared to the 3D scan obtained using photogrammetry or from 56% to 2.5% compared to a convex hull of this 3D scan. This also has the added benefit of producing more accurate canopy volume estimations which are important for common precision viticulture management processes such as variable rate applications.

Low-frequency sound absorption of a tunable multilayer composite structure

2021 ◽  
pp. 107754632110082
Author(s):  
Hanbo Shao ◽  
Jincheng He ◽  
Jiang Zhu ◽  
Guoping Chen ◽  
Huan He
Keyword(s):  
Porous Material ◽  
Absorption Coefficient ◽  
Composite Structure ◽  
Low Frequency ◽  
Acoustic Absorption ◽  
Multilayer Composite ◽  
Absorption Frequency ◽  
Acoustic Absorption Coefficient ◽  
Simulation And Experiment ◽  
Single Material

Our work investigates a tunable multilayer composite structure for applications in the area of low-frequency absorption. This acoustic device is comprised of three layers, Helmholtz cavity layer, microperforated panel layer, and the porous material layer. For the simulation and experiment in our research, the absorber can fulfill a twofold requirement: the acoustic absorption coefficient can reach near 0.8 in very low frequency (400 Hz) and the range of frequency is very wide (400–3000 Hz). In all its absorption frequency, the average of the acoustic absorption coefficient is over 0.9. Besides, the absorption coefficient can be tunable by the scalable cavity. The multilayer composite structure in our article solved the disadvantages in single material. For example, small absorption coefficient in low frequency in traditional material such as microperforated panel and porous material and narrow reduction frequency range in acoustic metamaterial such as Helmholtz cavity. The design of the composite structure in our article can have more wide application than single material. It can also give us a novel idea to produce new acoustic devices.

scholarly journals Dual-Band RF Wireless Power Transfer System with a Shared-Aperture Dual-Band Tx Array Antenna

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3803
Author(s):  
Chan-Mi Song ◽  
Hong-Jun Lim ◽  
Son Trinh-Van ◽  
Kang-Yoon Lee ◽  
Youngoo Yang ◽  
...  
Keyword(s):  
Wireless Power Transfer ◽  
Transmission Efficiency ◽  
Array Antenna ◽  
Dual Band ◽  
Single Frequency ◽  
Power Transfer ◽  
Wireless Power ◽  
Beam Focusing ◽  
Received Power ◽  
Rf Wireless

In this paper, a dual-band RF wireless power transfer (WPT) system with a shared-aperture dual-band Tx array antenna for 2.4 and 5.8 GHz is proposed. The final configuration of the Tx array, which is made up of 2.4 GHz right-handed circular polarization (RHCP) patches and 5.8 GHz RHCP patches, is derived from the optimization of 2.4 and 5.8 GHz thinned arrays, ultimately to achieve high transmission efficiency for various WPT scenarios. The dual-band RF WPT Tx system including the Tx array antenna and a Tx module is implemented, and Rx antennas with a 2.4 GHz patch, a 5.8 GHz patch, and a dual-band (2.4 and 5.8 GHz) patch are developed. To validate the proposed dual-band RF WPT system, WPT experiments using a single band and dual bands were conducted. When transmitting RF wireless power on a single frequency (either 2.482 GHz or 5.73 GHz), the received power according to the distance between the Tx and Rx and the position of the Rx was measured. When the distance was varied from 1 m to 3.9 m and the transmitted power was 40 dBm, the received power value at 2.482 GHz and 5.73 GHz were measured and found to be 24.75–13.5 dBm (WPT efficiency = 2.985–0.224%) and 19.25–6.8 dBm (WPT efficiency = 0.841–0.050%), respectively. The measured results were in good agreement with the calculated results, and it is revealed that the transmission efficiency when wireless power is transmitted via beam-focusing increases more than that with conventional beam-forming. Furthermore, the dual-band WPT experiment proves that 2.482 GHz beam and 5.73 GHz beams can be formed individually and that their wireless power can be transmitted to a dual-band Rx or two different Rx.

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