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A wireless magnetic resonance energy transfer system for micro implantable medical sensors.

Li X, Zhang H, Peng F, Li Y, Yang T, Wang B, Fang D - Sensors (Basel) (2012)

Bottom Line: The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system.In addition, the output current varies with changes in the distance.The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm(3).

View Article: PubMed Central - PubMed

Affiliation: School of Electronics and Information Engineering, Beijing Jiaotong University, Beijing 100044, China. lixiuhan@bjtu.edu.cn

ABSTRACT
Based on the magnetic resonance coupling principle, in this paper a wireless energy transfer system is designed and implemented for the power supply of micro-implantable medical sensors. The entire system is composed of the in vitro part, including the energy transmitting circuit and resonant transmitter coils, and in vivo part, including the micro resonant receiver coils and signal shaping chip which includes the rectifier module and LDO voltage regulator module. Transmitter and receiver coils are wound by Litz wire, and the diameter of the receiver coils is just 1.9 cm. The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system. When the distance between the transmitter coils and the receiver coils is 1.5 cm, the transfer efficiency is 85% at the frequency of 742 kHz. The power transfer efficiency can be optimized by adding magnetic enhanced resonators. The receiving voltage signal is converted to a stable output voltage of 3.3 V and a current of 10 mA at the distance of 2 cm. In addition, the output current varies with changes in the distance. The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm(3).

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Related in: MedlinePlus

(a) η of two- and four-coil systems versus distance. (b) η of four-coil system with magnetic enhanced resonators under different gaps at the distance of 5 cm.
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f11-sensors-12-10292: (a) η of two- and four-coil systems versus distance. (b) η of four-coil system with magnetic enhanced resonators under different gaps at the distance of 5 cm.

Mentions: Figure 11(a) is the measurement results of the power transfer efficiency (η) versus different distance for two- and four-coil system. η of four-coil system is much higher than that of two-coil system in the measurement range (1 cm∼7 cm). It indicates that the four-coil power transfer system can meet different kinds of sensors' power demands. The power of 33 mW can be delivered at the distance of 2 cm. η of the four-coil system is 85% at the distance of 1.5 cm (rm/d = 0.9), which is much higher than 43% of the two-coil system. The highest η is 86% at the distance of 1 cm. What's more, η is little affected by the distance when the distance is less than 2 cm. Even if the distance is 3 cm, the efficiency is as high as 24%.


A wireless magnetic resonance energy transfer system for micro implantable medical sensors.

Li X, Zhang H, Peng F, Li Y, Yang T, Wang B, Fang D - Sensors (Basel) (2012)

(a) η of two- and four-coil systems versus distance. (b) η of four-coil system with magnetic enhanced resonators under different gaps at the distance of 5 cm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472828&req=5

f11-sensors-12-10292: (a) η of two- and four-coil systems versus distance. (b) η of four-coil system with magnetic enhanced resonators under different gaps at the distance of 5 cm.
Mentions: Figure 11(a) is the measurement results of the power transfer efficiency (η) versus different distance for two- and four-coil system. η of four-coil system is much higher than that of two-coil system in the measurement range (1 cm∼7 cm). It indicates that the four-coil power transfer system can meet different kinds of sensors' power demands. The power of 33 mW can be delivered at the distance of 2 cm. η of the four-coil system is 85% at the distance of 1.5 cm (rm/d = 0.9), which is much higher than 43% of the two-coil system. The highest η is 86% at the distance of 1 cm. What's more, η is little affected by the distance when the distance is less than 2 cm. Even if the distance is 3 cm, the efficiency is as high as 24%.

Bottom Line: The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system.In addition, the output current varies with changes in the distance.The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm(3).

View Article: PubMed Central - PubMed

Affiliation: School of Electronics and Information Engineering, Beijing Jiaotong University, Beijing 100044, China. lixiuhan@bjtu.edu.cn

ABSTRACT
Based on the magnetic resonance coupling principle, in this paper a wireless energy transfer system is designed and implemented for the power supply of micro-implantable medical sensors. The entire system is composed of the in vitro part, including the energy transmitting circuit and resonant transmitter coils, and in vivo part, including the micro resonant receiver coils and signal shaping chip which includes the rectifier module and LDO voltage regulator module. Transmitter and receiver coils are wound by Litz wire, and the diameter of the receiver coils is just 1.9 cm. The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system. When the distance between the transmitter coils and the receiver coils is 1.5 cm, the transfer efficiency is 85% at the frequency of 742 kHz. The power transfer efficiency can be optimized by adding magnetic enhanced resonators. The receiving voltage signal is converted to a stable output voltage of 3.3 V and a current of 10 mA at the distance of 2 cm. In addition, the output current varies with changes in the distance. The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm(3).

Show MeSH
Related in: MedlinePlus