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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

Optimized Q factor versus Na and Nt for every coil (a) Q1versus Na, Nt for coil1; (b) Q2versus Na, Nt for coil2; (c) Q3versus Na, Nt for coil3; (d) Q4versus Na, Nt for coil4.
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f2-sensors-12-10292: Optimized Q factor versus Na and Nt for every coil (a) Q1versus Na, Nt for coil1; (b) Q2versus Na, Nt for coil2; (c) Q3versus Na, Nt for coil3; (d) Q4versus Na, Nt for coil4.

Mentions: Substituting Equations (1–3,5–7) into Equation (4), Matlab is used to calculate the tendency of Q versus Na and Nt, as shown in Figure 2. The resonant frequency of the four coils is set at 650 kHz according to the operating frequency of AWG44 Litz wire, and the load resistance (Rload = 50 Ω) for coil1 and coil4. According to the optimized Q and Equation (1), the self-inductance La and a group of optimized geometry parameters are given in Table 1. The optimized inner diameters are set as coil1 of 34 mm, coil2 of 36 mm, coil3 of 14 mm, and coil4 of 16.5 mm.


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)

Optimized Q factor versus Na and Nt for every coil (a) Q1versus Na, Nt for coil1; (b) Q2versus Na, Nt for coil2; (c) Q3versus Na, Nt for coil3; (d) Q4versus Na, Nt for coil4.
© Copyright Policy
Related In: Results  -  Collection

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

f2-sensors-12-10292: Optimized Q factor versus Na and Nt for every coil (a) Q1versus Na, Nt for coil1; (b) Q2versus Na, Nt for coil2; (c) Q3versus Na, Nt for coil3; (d) Q4versus Na, Nt for coil4.
Mentions: Substituting Equations (1–3,5–7) into Equation (4), Matlab is used to calculate the tendency of Q versus Na and Nt, as shown in Figure 2. The resonant frequency of the four coils is set at 650 kHz according to the operating frequency of AWG44 Litz wire, and the load resistance (Rload = 50 Ω) for coil1 and coil4. According to the optimized Q and Equation (1), the self-inductance La and a group of optimized geometry parameters are given in Table 1. The optimized inner diameters are set as coil1 of 34 mm, coil2 of 36 mm, coil3 of 14 mm, and coil4 of 16.5 mm.

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