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

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.

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

Physica Scripta ◽

10.1088/1402-4896/ac4a3a ◽

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.

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Low-cost wireless power efficiency optimization of the NFC tag through switchable receiver antenna

Wireless Power Transfer ◽

10.1017/wpt.2018.1 ◽

2018 ◽

Vol 5 (2) ◽

pp. 87-96 ◽

Cited By ~ 1

Author(s):

Yi Zhao ◽

Huaye Li ◽

Saman Naderiparizi ◽

Aaron Parks ◽

Joshua R. Smith

Keyword(s):

Power Efficiency ◽

Low Cost ◽

Near Field ◽

Power Delivery ◽

Wireless Power ◽

Load Impedance ◽

Communication Performance ◽

Sensing Platform ◽

Varied Range ◽

Range Alignment

Near-field communication (NFC) readers, ubiquitously embedded in smartphones and other infrastructures can wirelessly deliver mW-level power to NFC tags. Our previous work NFC-wireless identification and sensing platform (WISP) proves that the generated NFC signal from an NFC enabled phone can power a tag (NFC-WISP) with display and sensing capabilities in addition to identification. However, accurately aligning and placing the NFC tag's antenna to ensure the high power delivery efficiency and communication performance is very challenging for the users. In addition, the performance of the NFC tag is not only range and alignment sensitive but also is a function of its run-time load impedance. This makes the execution of power-hungry tasks on an NFC tag (like the NFC-WISP) very challenging. Therefore, we explore a low-cost tag antenna design to achieve higher power delivered to the load (PDL) by utilizing two different antenna configurations (2-coil/3-coil). The two types of antenna configurations can be used to dynamically adapt to the requirements of varied range, alignment and load impedance in real-time, therefore, we achieve continuous high PDL and reliable communication. With the proposed method, we can, for example, turn a semi-passive NFC-WISP into a passive display tag in which an embedded 2.7″ E-ink screen can be updated robustly by a tapped NFC reader (e.g. an NFC-enable cell-phone) over a 3 seconds and within 1.5cm range.

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New Design Topology of High-Q Factor Printed Antenna having Unequal Width and Pitch used for Near-field Wireless Power Transmission

IEEE Journal of Emerging and Selected Topics in Power Electronics ◽

10.1109/jestpe.2021.3101477 ◽

2021 ◽

pp. 1-1

Author(s):

Jinhyong Kim ◽

Cheolung Cha ◽

Jungsuek Oh ◽

Yongtaek Hong

Keyword(s):

Power Transmission ◽

Near Field ◽

Q Factor ◽

Wireless Power ◽

Printed Antenna ◽

Wireless Power Transmission ◽

High Q

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

Frequenz ◽

10.1515/freq-2021-0035 ◽

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.

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Textile-Based Coils for Inductive Wireless Power Transmission

Applied Sciences ◽

10.3390/app11094309 ◽

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.

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Printed Split-Ring Loops with High Q-Factor for Wireless Power Transmission

Electronics ◽

10.3390/electronics10222884 ◽

2021 ◽

Vol 10 (22) ◽

pp. 2884

Author(s):

Jingchen Wang ◽

Mark Paul Leach ◽

Eng Gee Lim ◽

Zhao Wang ◽

Rui Pei ◽

...

Keyword(s):

Power Transmission ◽

Transfer Efficiency ◽

Q Factor ◽

Power Transfer ◽

Wireless Power ◽

Wireless Power Transmission ◽

Split Ring ◽

Spiral Coil ◽

High Q ◽

Power Transfer Efficiency

The use of printed spiral coils (PSCs) as inductors in the construction of Wireless Power Transmission (WPT) circuits can save space and be integrated with other circuit boards. The challenges and issues of PSCs present for WPT mainly relate to maintaining an inductive characteristic at frequencies in Ultra High Frequency (UHF) band and to maximising the power transfer efficiency (PTE) between primary and secondary circuits. A new technique is proposed to increase the Q-factor relative to that offered by the PSC, which is shown to enhance WPT performance. This paper provides four-turn planar split-ring loops with high Q-factor for wireless power transmission at UHF bands. This design enhances the power transfer efficiency more than 12 times and allows for a greater transfer distance from 5 mm to 20 mm, compared with a conventional planar rectangular spiral coil.

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High-efficiency and compact WPT receiving antenna design using simulation optimization method

International Journal of Electrical Engineering Education ◽

10.1177/0020720921989014 ◽

2021 ◽

pp. 002072092198901

Author(s):

Yanghyun Kim ◽

Chulhun Seo

Keyword(s):

Machine Learning ◽

High Efficiency ◽

Optimization Method ◽

Transmission Efficiency ◽

Learning Technology ◽

Q Factor ◽

Power Transfer ◽

Wireless Power ◽

High Q ◽

Receiving Antenna

In this paper, a high-efficiency and compact wireless power transfer (WPT) receiving antenna using an flexible printed circuits board (FPCB) with high-Q factor is proposed. The proposed high-efficiency and compact WPT receiving antenna consists of a spiral structure, a lumped element and via through the ground structure. In this paper, in order to design a miniaturized high-efficiency WPT receiving antenna, machine learning technology was used to optimally design the antenna pattern that affects the Q factor. The designed receiving antenna has improved wireless power transmission efficiency with high Q characteristics. The power transfer efficiency is above 88% from distance 10 mm and the resonant frequency is 110 MHz. The sizes of the receiving antenna and the NFC antenna are 30 × 40 mm and 20 × 30 mm, respectively. Machine learning was used to design and fabricate the composite module of a WPT receiving antenna and NFC antenna. Comparison of the experimental results of the proposed receiving antenna with a general receiving antenna confirms the improvement in transmission efficiency.

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Compensating Resonant Frequency via Adjusting Adjustable Coil Automatically

Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) ◽

10.2174/2352096511666180705114908 ◽

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.

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