Patterning of Subwavelength Magnetic Fields Along a Line by Means of Spatial Spectrum: Design and Implementation

Hajiaghajani, Amirhossein; Abdolali, Ali

doi:10.1109/lmag.2017.2746065

Cited by 9 publications

(8 citation statements)

References 20 publications

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“…To this aim, the spatial forming of subwavelength magnetic fields is a potential solution and may enable the control of the produced magnetic field and the formation of a single-sided radiation pattern aimed only at the Rx coils and away from the lossy media [12,27,28,29]. A traditional method to focus the magnetic field and suppress its leakage has been introduced by Halbach [30], which has since been the basis of a multitude of biomedical treatments such as magnetic drug delivery [31,32,33].…”

Section: Introductionmentioning

confidence: 99%

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

Hajiaghajani

Ahn

2019

Micromachines

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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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Section: Introductionmentioning

confidence: 99%

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

Hajiaghajani

Ahn

2019

Micromachines

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“…In this paper, a novel structure of magnetic field patterning is proposed based on the spatial spectrum of the arbitrary pattern. This builds on our preliminary study to form magnetic fields in one dimension [Hajiaghajani and Abdolali, ]. We present a setup of programmable subwavelength coils to obtain arbitrary‐patterned perpendicular magnetic fields in a plane, e.g., z ‐plane.…”

Section: Introductionmentioning

confidence: 99%

Magnetic field pattern synthesis and its application in targeted drug delivery: Design and implementation

Hajiaghajani

Abdolali

2018

Bioelectromagnetics

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In cancer therapy, magnetic drug targeting is considered as an effective treatment to reduce chemotherapy's side effects. The accurate design and shaping of magnetic fields are crucial for healthy cells to be immune from chemotherapeutics. In this paper, arbitrary 2-dimensional spatial patterns of magnetic fields from DC to megahertz are represented in terms of spatial Fourier spectra with sinusoidal eigenfunctions. Realization of each spatial frequency was investigated by a set of elliptical coils. Therefore, it is shown that the desired pattern was synthesized by simultaneous use of coil sets. Currents running on each set were obtained via fast and straightforward analytical Fourier series calculation. Experimentally scanned sample patterns were in close agreement with full wave analysis. Discussions include the evaluation of the Fourier series approximation error and cross-polarization of produced magnetic fields. It was observed that by employing the controlled magnetic field produced by the proposed setup, we were able to steer therapeutic particles toward the right or left half-spheres of the breast, with an efficiency of 90%. Such a pattern synthesizer may be employed in numerous human arteries as well as other bioelectromagnetic patterning applications, e.g., wireless power transfer, magnetic innervation, and tomography. Bioelectromagnetics. 39:325-338, 2018. © 2018 Wiley Periodicals, Inc.

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“…However, various methods have been introduced to control electric and magnetic fields at low frequencies such as lowfrequency lenses [21][22][23][24] composed of an array of loops. Another method is to use an array of coils [25][26][27]. In this method, the sources and location of coils are determined in order to achieve the desired field.…”

Section: Introductionmentioning

confidence: 99%

Manipulation of the electromagnetic near‐fields by 3D printed coils: from design to fabrication

Jafari

Abdolali

2018

IET Microwaves, Antennas & Propagation

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Nowadays, the advancements in three‐dimensional (3D) printing technology have made it possible for sophisticated structures to be fabricated fast, accurate, and affordable. In this study, a new method is proposed for the manipulation of near‐electric and magnetic fields based on 3D coils. The manipulation of near‐fields is widely used in various electromagnetic problems. The 3D coils lead to 3D distributions of current paths. By changing the shape of the coil (i.e. the current path) the desired electric field or magnetic field can be achieved. During the design procedure, at first dyadic Green's functions are used to calculate the electric and magnetic fields. Also, proper basis functions are used to define the current paths. Following that, with the help of genetic algorithm, the coefficients of the basis functions, and thus the shape of 3D coils are derived for the realisation of the desired field. Finally, this method is used to realise a normal distribution on a curved path. The coils are fabricated with fused deposition modeling (FDM) 3D printing technology and by attaching the conductive wires to the printed structure. The results of design, numerical simulations, and experimental tests indicate the high performance of this technique for manipulation of near‐electric and magnetic fields.

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Patterning of Subwavelength Magnetic Fields Along a Line by Means of Spatial Spectrum: Design and Implementation

Cited by 9 publications

References 20 publications

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

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

Magnetic field pattern synthesis and its application in targeted drug delivery: Design and implementation

Manipulation of the electromagnetic near‐fields by 3D printed coils: from design to fabrication

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