Abstract
In this paper, we investigate the possibility of improving efficiency in non-radiative wireless power transfer (WPT) using metasurfaces embedded between two current varying coils and present a complete theoretical analysis of this system. We use a point-dipole approximation to calculate the fields of the coils. Based on this method, we obtain closed-form and analytical expressions which would provide basic insights into the possibility of efficiency improvement with metasurface. In our analysis, we use the equivalent two sided surface impedance model to analyze the metasurface and to show for which equivalent surface impedance the WPT efficiency will be maximized at the design frequency. Then, to validate our theory, we perform a full-wave simulation for analyzing a practical WPT system, including two circular loop antennas at 13.56 MHz. We then design a metasurface composed of single-sided CLSRRs to achieve a magnetic lensing based on the calculated equivalent surface impedance. The analytical results and full-wave simulations indicated non-radiative WPT efficiency improvement due to amplifying the near evanescent field which can be achieved through inserting the proposed metasurface.
Highlights
We investigate the possibility of improving efficiency in non-radiative wireless power transfer (WPT) using metasurfaces embedded between two current varying coils and present a complete theoretical analysis of this system
We have shown that using a proper equivalent inductive surface impedance embedded between the two magnetic dipoles of the WPT system, a metasurface could be designed for refocusing the flux due to the transmitter coil at the receiver coil and surface wave amplification
Our analytical expressions have confirmed that WPT efficiency can be improved by designing a proper metasurface, which is predictable
Summary
We investigate the possibility of improving efficiency in non-radiative wireless power transfer (WPT) using metasurfaces embedded between two current varying coils and present a complete theoretical analysis of this system. In the near-filed region or non-radiative WPT, energy is transferred through near-field electromagnetic waves from the source to receiver9 In this WPT scheme, the operational distance between the transmitter and receiver is far shorter than the wavelength which is suitable for charging electrical devices with short and midrange distance. In13, the effect of metamaterial on WPT efficiency improvement has been investigated employing a simplified geometry such as an infinitely large slab and point dipoles for the source and receiver to obtain a closed form and analytical expressions Another original approach to manipulating electromagnetic wave for WPT efficiency enhancement is use of metasurface instead of metamaterial slab. We use a point-dipole approximation to calculate the fields of the coils Based on this method, we obtain closed-form and analytical expressions which would provide initial insights into the possibility of efficiency improvement with metasurface
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