Tracking Optimal Efficiency of Magnetic Resonance Wireless Power Transfer System for Biomedical Capsule Endoscopy

Magnetic resonance coupling circuits have four general topologies; however, there is a lack of comprehensive theoretical analysis with experimental verification for each of these topologies regarding their attractiveness for wireless power transfer (WPT). This article provides this for each of the four topologies to fully understand their differences and allow the selection of the most appropriate type based on system requirements. In addition, a problem associated with the resonance coupling method is the phenomenon of frequency splitting, which can lead to a high‐power transfer efficiency but low‐load power at the resonant frequency. Reasons for frequency splitting and methods of circumventing the problem will be illustrated in this article. Of the four topologies, the series‐parallel (SP) (input‐output) circuit configuration is the most efficient for the realization of a WPT system with a large load impedance, in terms of achieving both a high power transfer efficiency and high‐load power.

Section: Introductionmentioning

confidence: 99%

Investigation of magnetic resonance coupling circuit topologies for wireless power transmission

Wang

Leach

Lim

et al. 2019

“…Many efforts to design and analyze such a WPT system have been conducted. In particular, the related research for a maximum power transfer efficiency (PTE) has been conducted . Due to the impedance matching characteristics of the WPT system using the coupled resonant coils, the PTE of the WPT system has degraded on the different operating distances .…”

Section: Introductionmentioning

confidence: 99%

A compact module‐integrated wireless power transfer system with a square metal plate

Ahn

Lee

2019

In this article, we propose a compact module‐integrated wireless power transfer (WPT) system for miniaturizing a WPT system and improving power transfer efficiency (PTE) within the operating distance. Using an eddy current (and its associated magnetic field) formed in a module‐integrated square metal plate, the proposed WPT system realizes a uniform mutual inductance between the coils within the operating distance and achieves an improved PTE of up to 54.7% at 6.78 MHz compared to the conventional WPT system.

“…Recently, RF (radio frequency) based wireless power transfer has become an interesting topic for an energy transmission without any wires to electronics devices such as mobile, smart sensors, electric car, and implanted medical sensors, Rectenna (rectifying antenna) is one of the key components in RF wireless power transfer. Comparing with other WPT (wireless power transfer) methods using magnetic coupling or resonance, RF WPT using antennas is more appropriate than other methods for a long distance energy transfer.…”

Section: Introductionmentioning

confidence: 99%

High gain pentagonal loop rectifying antenna

Ahn

2018

In this article, a high gain rectifying antenna using a pair of pentagonal loops has been developed for wireless power transfer at 5.8 GHz. For a long range wireless power transfer, the rectenna system requires high gain and high conversion efficiency. The proposed rectenna system consists of a pair of pentagonal loop antennas to achieve high gain characteristics, an impedance transformer, and a rectifying circuit which are designed on a CPS (Coplanar stripline) structure. A metal reflector is also placed for achieving higher gain characteristics in a broadside direction. A CPS to microstrip line balun is designed to verify performance of the pentagonal loop antennas based on CPS structure. The fabricated pentagonal antenna demonstrates high gain of 10.1 dBi, and it results in receiving more RF energy from a designated source. An impedance transformer is designed to change the antenna's input impedance to diode's input impedance and block higher order signals coming back from the rectifying diode. To obtain high conversion efficiency, several load resistors are used. The proposed rectenna system based on CPS pentagonal loops shows measured conversion efficiency of 75% at 5.8 GHz, and its performance has been verified through simulation and measurement.