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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

Description of the coils: (a) Description of the structure of the coils; (b) The size of the transmitter and receiver coils compared with a coin.
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f9-sensors-12-10292: Description of the coils: (a) Description of the structure of the coils; (b) The size of the transmitter and receiver coils compared with a coin.

Mentions: A detachable stent with variable dimensions was designed to accommodate different sizes of the coils, which can be removed to further reduce the volume of the coil. The structure of the coils is described in Figure 9(a), where coil2 is wrapped over coil1 and coil3 is wrapped over coil4. Sixty-strand and seven-strand Litz wire of AWG 44 are used to implement the transmitter coils (coil1, coil2) and receiver coils (coil3, coil4), respectively. Figure 9(b) shows the transmitter and receiver coils compared with a Chinese coin (diameter = 25 mm). Table 2 gives the geometric specifications and measured L and Q of the four coils according to the theoretically optimized results as shown in Table 1. The measured L and Q at the frequency of 742 kHz are also given in Table 2.


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)

Description of the coils: (a) Description of the structure of the coils; (b) The size of the transmitter and receiver coils compared with a coin.
© Copyright Policy
Related In: Results  -  Collection

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

f9-sensors-12-10292: Description of the coils: (a) Description of the structure of the coils; (b) The size of the transmitter and receiver coils compared with a coin.
Mentions: A detachable stent with variable dimensions was designed to accommodate different sizes of the coils, which can be removed to further reduce the volume of the coil. The structure of the coils is described in Figure 9(a), where coil2 is wrapped over coil1 and coil3 is wrapped over coil4. Sixty-strand and seven-strand Litz wire of AWG 44 are used to implement the transmitter coils (coil1, coil2) and receiver coils (coil3, coil4), respectively. Figure 9(b) shows the transmitter and receiver coils compared with a Chinese coin (diameter = 25 mm). Table 2 gives the geometric specifications and measured L and Q of the four coils according to the theoretically optimized results as shown in Table 1. The measured L and Q at the frequency of 742 kHz are also given in Table 2.

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