Metamaterials for Improving Efficiency of Magnetic Resonant Wireless Power Transfer Applications

Abstract

In this article, we investigate a compact metamaterial structure for enhancing a magnetic resonant wireless power transfer (WPT) system operated at 6.5 MHz. A thin magnetic metamaterial (MM) slab placed between the transmitter (Tx) and receiver (Rx) coil can improve WPT efficiency. The metamaterial unit cell is designed by a ten-turn spiral resonator (10T-SR) loaded with an external capacitor. The resonant frequency of MM unit cells can be easily controlled by changing the capacitor value. By using the optimization approach, we achieve a significant WPT efficiency improvement at a mid-range distance. The results showed an enhancement of the magnetic field in the WPT system when MM slab was present. This demonstrates the ability to amplify the evanescent wave of MM slab, thereby improving the WPT efficiency. The transmission coefficients of WPT system at 60 cm increased from 0.5 to 0.76 with MM slab, which corresponds to a 46% improvement.

Research on the performance improvement of MCR-WPT by hyperscatterers

“…The load R L is set to 50Ω. (5) After the establishment of the system, the transmitting coil is placed at the center of the offset spherical superscatterer, dis=0.1 m. The parameters of the transmitting coil after the equivalent amplification displacement are the same as those of the receiving coil, dis , =0.4 m. The magnetic field distribution of the system is shown in Fig. 3, (a) the magnetic field of the transmitting coil is small and the magnetic field of the receiving coil is weak when no superscatterer is added; (b) the magnetic fields of the transmitting coil and the receiving coil after the loading of superscatterer are significantly stronger compared with (a); (c) the magnetic fields of the transmitting coil and the receiving coil after the equivalent amplification displacement of 4 times are the same as those of the transmitting coil and the receiving coil after (b) loading of superscatterer.…”

“…In order to improve the performance of WPT systems, the method of regulating magnetic field based on electromagnetic metamaterials has been widely studied.In 2006, J.B. Pendry proposed a new design method of electromagnetic metamaterials, the optical coordinate transformation method [4], which realizes the method of electromagnetic field regulation based on the optical transformation theory. From 2014, the theoretical analysis, simulation and experimental verification of magnetic focusers, superscatterers, and displacement plates designed by the optical transformation method applied to WPT systems began to be published publicly one after another [5]. At present, the most commonly used electromagnetic metamaterial in the WPT system is the negative magnetic metamaterial plate, which has the effect of electromagnetic aggregation.…”