scholarly journals Near Field Wireless Powering of Deep Medical Implants

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2720 ◽  
Author(s):  
Tommaso Campi ◽  
Silvano Cruciani ◽  
Valerio De Santis ◽  
Francesca Maradei ◽  
Mauro Feliziani
Keyword(s):  
Magnetic Field ◽  
Uniform Magnetic Field ◽  
Near Field ◽  
Cylindrical Shape ◽  
Medical Implants ◽  
Wireless Power ◽  
Primary Coil ◽  
Fixed Position ◽  
Safety Standards ◽  
Large Primary

This study deals with the inductive-based wireless power transfer (WPT) technology applied to power a deep implant with no fixed position. The usage of a large primary coil is here proposed in order to obtain a nearly uniform magnetic field inside the human body at intermediate frequencies (IFs). A simple configuration of the primary coil, derived by the Helmholtz theory, is proposed. Then, a detailed analysis is carried out to assess the compliance with electromagnetic field (EMF) safety standards. General guidelines on the design of primary and secondary coils are provided for powering or charging a deep implant of cylindrical shape with or without metal housing. Finally, three different WPT coil demonstrators have been fabricated and tested. The obtained results have demonstrated the validity of the proposed technology.

scholarly journals Optimization of a Two-Layer 3D Coil Structure with Uniform Magnetic Field

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Davor Vinko ◽  
Domagoj Bilandžija ◽  
Vanja Mandrić Radivojević
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Field Distribution ◽  
Uniform Magnetic Field ◽  
Optimization Method ◽  
Magnetic Field Distribution ◽  
Wireless Power ◽  
Average Magnetic Field ◽  
Coil Structure

Conventional magnetically coupled resonant wireless power transfer systems are faced with resonant frequency splitting phenomena and impedance mismatch when a receiving coil is placed at misaligned position. These problems can be avoided by using uniform magnetic field distribution at receiving plane. In this paper, a novel 3D transmitting coil structure with improved uniform magnetic field distribution is proposed based on a developed optimization method. The goal is to maximize the average magnetic field strength and uniform magnetic field section of the receiving plane. Hence, figures of merit (FoM1 and FoM2) are introduced and defined as product of average magnetic field strength and length or surface along which uniform magnetic field is generated, respectively. The validity of the optimization method is verified through laboratory measurements performed on the fabricated coils driven by signal generator at operating frequency of 150 kHz. Depending on the allowed ripple value and predefined coil proportions, the proposed transmitting coil structure gives the uniform magnetic field distribution across 50% to 90% of the receiving plane.

scholarly journals Single-Sided Near-Field Wireless Power Transfer by A Three-Dimensional Coil Array

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 200 ◽  
Author(s):  
Amirhossein Hajiaghajani ◽  
Seungyoung Ahn
Keyword(s):  
Magnetic Field ◽  
Printed Circuit Boards ◽  
Signal To Noise Ratio ◽  
Near Field ◽  
3D Structure ◽  
Three Dimensional ◽  
Power Transfer ◽  
Circuit Boards ◽  
Wireless Power ◽  
Halbach Arrays

Wirelessly powered medical microrobots are often driven or localized by magnetic resonance imaging coils, whose signal-to-noise ratio is easily affected by the power transmitter coils that supply the microrobot. A controlled single-sided wireless power transmitter can enhance the imaging quality and suppress the radiation leakage. This paper presents a new form of electromagnet which automatically cancels the magnetic field to the back lobes by replacing the traditional circular coils with a three-dimensional (3D) coil scheme inspired by a generalized form of Halbach arrays. It is shown that, along with the miniaturization of the transmitter system, it allows for improved magnetic field intensity in the target side. Measurement of the produced magnetic patterns verifies that the power transfer to the back lobe is 15-fold smaller compared to the corresponding distance on the main lobe side, whilst maintaining a powering efficiency similar to that of conventional planar coils. To show the application of the proposed array, a wireless charging pad with an effective powering area of 144 cm2 is fabricated on 3D-assembled printed circuit boards. This 3D structure obviates the need for traditional magnetic shield materials that place limitations on the working frequency and suffer from non-linearity and hysteresis effects.

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