Wireless power transfer enhanced by metamaterials

[jos]

 

Tongji researchers have embedded magnetic metamaterials into the coils used in non-radiative wireless power transfer, which is the method used by most of today's wireless power transfer applications. In the researchers' design, one coil creates a magnetic field, which is captured by the second coil as voltage.

 

Like all metamaterials, the ones used here contain subwavelength microstructures that can manipulate electromagnetic waves in ways not possible with other materials. Here, the metamaterials are assembled with "meta-atoms," which are 2.6-cm etchings on the spiral copper coils.

This particular size of 2.6 cm is important because it allows for strong coupling between the deep subwavelength resonant modes of the meta-atoms, and this coupling is responsible for increasing the transfer efficiency.

"By embedding metamaterials into non-resonant coils, the overall efficiency of the wireless power transfer system is found to be greatly enhanced, due to the coupling between metamaterials," the researchers wrote in their paper.

Although the efficiency decays quickly as distance increases—from 32% at 3 cm to 15% at 5 cm—the 20% efficiency near 4 cm marks a sweet spot for certain applications, such as wireless charging of pacemakers and other medical devices.

 

 

Source: Wireless power transfer based on magnetic metamaterials consisting of assembled ultra-subwavelength meta-atoms

[Glenwing]

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