Midfield Wireless Powering for Implantable Systems

Ho, John S.; Kim, Sanghoek; Poon, Ada S. Y.

doi:10.1109/jproc.2013.2251851

Cited by 198 publications

(110 citation statements)

References 38 publications

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“…This enables parametrization of the intrinsic losses, the coupling between the structures, and the power extracted by the load through the inputs and outputs at these ports. Various formalisms have been adopted for energy transfer, including impedance parameters [8], scattering matrices [23], and coupled-mode theory [20,24,25]. These formalisms differ in the inputs and outputs (specified by voltages, currents, power amplitudes, or modal amplitudes), although all such descriptions are fundamentally based on linearity of Maxwell's equations in the source terms.…”

Section: Coupled Structuresmentioning

confidence: 99%

See 1 more Smart Citation

ENERGY TRANSFER FOR IMPLANTABLE ELECTRONICS IN THE ELECTROMAGNETIC MIDFIELD (Invited Paper)

Ho¹,

Poon²

2014

PIER

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Abstract-The wireless transfer of electromagnetic energy into the human body could power medical devices and enable new ways to treat various disorders. To control energy transfer, metal structures are used to generate and manipulate radio-frequency electromagnetic fields. Most systems for transfer across the biological tissue operate in the quasi-static limit, but operation beyond this regime could afford new powering capabilities. This review discusses some recent developments in the design and implementation of systems operating in the electromagnetic midfield, where transfer exploits wave-like fields in the body.

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Section: Coupled Structuresmentioning

confidence: 99%

“…To direct energy from outside of the body, much research has been devoted to designing suitable electromagnetic structures [6][7][8]. Most of these structures are typically understood in terms of near-field (quasi-static) approximations to Maxwell's equations.…”

Section: Introductionmentioning

confidence: 99%

ENERGY TRANSFER FOR IMPLANTABLE ELECTRONICS IN THE ELECTROMAGNETIC MIDFIELD (Invited Paper)

Ho¹,

Poon²

2014

PIER

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“…In particular, ultrasonic links can achieve good power transmission efficiency (PTE) [4], but may not be suitable for powering multiple neural IMDs because of poor skull penetration and high sensitivity to depth/orientation. Mid-field powering (>1 GHz) can focus the electromagnetic (EM) field towards target IMDs at the cost of a reduced power delivery to the load (PDL) since the specific absorption rate (SAR) rapidly increases proportional to the square of frequency [5].…”

Section: Introductionmentioning

confidence: 99%

Millimeter-scale integrated and wirewound coils for powering implantable neural microsystems

Feng

Constandinou

Yeon

et al. 2017

2017 IEEE Biomedical Circuits and Systems Conference (BioCAS)

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Abstract-Next generation brain machine interfaces are targeting millimeter-scale implants that are freely floating and completely wireless. It is essential these systems achieve good power transmission efficiency but are also compatible with microsystem technologies. This paper presents two schemes for implementing mm-scale coils for power delivery by electromagnetic coupling -on-chip and wire-wound. A set of on-chip coils have been fabricated using a 0.35 µm CMOS technology with thick top metal option (3 µm aluminium). These achieve a maximum Qfactor of 16.37. The second approach describes wire-wound coils that have been fabricated using bondwire (25 µm gold), achieving a Q-factor of 24.54. This work develops the relevant analytical models, equivalent simulation models, and reports results using both finite element modeling (simulation) and experimental measurement of the fabricated devices. Finally, we compare results and discuss the relative merits of each approach.

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“…Inductive coupled coils in this weakly coupled regime are generally very inefficient [5]. Recently, it has been shown that by operating at GHz-range frequencies, much higher power transfer efficiency can be achieved for a mm-scaled receiver [6].…”

Section: Introductionmentioning

confidence: 99%

Non-Coil, Optimal Sources for Wireless Powering of Sub-Millimeter Implantable Devices

Kim¹,

Ho²,

Poon³

2017

PIER

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Abstract-This paper presents non-coil sources to improve the wireless power transfer efficiency for implantable device used in various medical applications -cardiovascular devices, endoscope in the small intestine, and neurostimulator in the brain. For each application, a bound on the power transfer efficiency and the optimal source achieving such bound are analytically solved. The results reveal that depending on the depth of the implantable devices, power can be transferred to a sub-millimeter scaled receiver with the efficiency ranging from −57 dB to −33 dB, which is up to 6.6 times higher than the performance of existing coil-based source systems. The technique introduced in this paper can be broadly applied to other medical applications.

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Midfield Wireless Powering for Implantable Systems

Cited by 198 publications

References 38 publications

ENERGY TRANSFER FOR IMPLANTABLE ELECTRONICS IN THE ELECTROMAGNETIC MIDFIELD (Invited Paper)

ENERGY TRANSFER FOR IMPLANTABLE ELECTRONICS IN THE ELECTROMAGNETIC MIDFIELD (Invited Paper)

Millimeter-scale integrated and wirewound coils for powering implantable neural microsystems

Non-Coil, Optimal Sources for Wireless Powering of Sub-Millimeter Implantable Devices

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