High-Q flexible spiral inductive coils

Ng, David C.; Boyd, Clive S.; Bai, Shun; Felic, G.; Halpern, M.E.; Skafidas, Efstratios

doi:10.1109/emcsa.2010.6141509

Cited by 8 publications

(3 citation statements)

References 6 publications

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“…It is worthwhile to note that the matching capacitors used need not be exact as the quality factor Q of the primary and secondary coils are not very high, typically about 50. However, techniques exist to optimize the topology of the tracks to increase Q [11].…”

Section: A Spice Simulationmentioning

confidence: 99%

Wireless power delivery for retinal prostheses

Williams

Allen

et al. 2011

2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Delivering power to an implanted device located deep inside the body is not trivial. This problem is made more challenging if the implanted device is in constant motion. This paper describes two methods of transferring power wirelessly by means of magnetic induction coupling. In the first method, a pair of transmit and receive coils is used for power transfer over a large distance (compared to their diameter). In the second method, an intermediate pair of coils is inserted in between transmit and receive coils. Comparison between the power transfer efficiency with and without the intermediate coils shows power transfer efficiency to be 11.5 % and 8.8 %, respectively. The latter method is especially suitable for powering implanted devices in the eye due to immunity to movements of the eye and ease of surgery. Using this method, we have demonstrated wireless power delivery into an animal eye.

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Section: A Spice Simulationmentioning

confidence: 99%

Wireless power delivery for retinal prostheses

Williams

Allen

et al. 2011

2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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“…is the average diameter of the flat spiral coil, and the fill ratio ∆ = (d ext − d inner )/(d ext + d inner ) which are defined in [10] to simplify the effect of dimensions for a coil with external diameter d ext and inner diameter dinner as shown in Figure 2. The ESRs of the coils are composed of their DC resistance, the skin effect, and the proximity effect [11]. The DC resistance of the coils can be calculated for a conductive track as:…”

Section: Theory Of Inductive Power Transmissionmentioning

confidence: 99%

“…Therefore, the inner diameter of the coil was set as 53 mm to get an integral number of turns for the coil. Ng et al [11] found that the optimal spacing depended on the size of coil and is essential to improve the unloaded Q factor. In this paper, the coils have a 2 mm spacing between conductive tracks, the spacing has been standardized at this value to reduce inter-turn proximity effects while leaving scope for the width of the conductive track to be varied within the overall coil-dimension limits.…”

Section: Designmentioning

confidence: 99%

Textile-Based Flexible Coils for Wireless Inductive Power Transmission

Grabham

Torah

et al. 2018

Applied Sciences

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Wireless inductive power transmission systems can potentially supply wearable devices. Power cables or batteries can be eliminated by implementing a wireless power transfer system, making the wearable devices less obtrusive to users. However, rigid coils can cause discomfort to users in wearable applications. The novel screen-printed flexible coils on textiles reported here are intended to be a low-cost and comfortable solution when integrated into clothing. A constant-width circular-spiral flat coil has been designed to minimize the detrimental effect of the low conductivity of the screen-printed flexible conductors on the efficiency of the wireless power transfer system. The coils are printed on 65/35 polyester/cotton textile with a screen-printed Fabink-UV-IF1 interface layer coating. The interface layer provides a relatively flat and smooth surface to prevent the permeation of the conductive paste into the textile and allows the printing of finer-profile coils. A 5 V 1.2 W DC output has been achieved by a wireless power transfer system using the printed flexible coils with Qi standard circuitry; a DC-DC efficiency of 37% has been measured.

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Design and modeling of PCB coils for inductive power charging

et al. 2015

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This article presents a modeling and parametric investigation of printed circuit board (PCB) coils used in inductive power charging systems by using intensive full-wave electromagnetic simulations. Low frequencies applications (below 1 MHz) are targeted. The proposed modeling approach and design methodology are validated for wireless power transfer systems including transmitting (Tx) and receiving (Rx) coils. The impact of ferrite materials used for shielding and efficiency improvement is also analyzed. Optimized PCB coils allowing a theoretical efficiency of 88.7% at 100 kHz and 98.5% at 1 MHz confirms that PCB coils are appropriate for wireless power transfer at such frequencies.

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High-Q flexible spiral inductive coils

Cited by 8 publications

References 6 publications

Wireless power delivery for retinal prostheses

Wireless power delivery for retinal prostheses

Textile-Based Flexible Coils for Wireless Inductive Power Transmission

Design and modeling of PCB coils for inductive power charging

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