Efficiency-Enhanced Holographic Metasurface for Wireless Power Transfer Based in Electric Vehicles

The widespread adoption of electric vehicles (EVs) critically hinges on the development of efficient and seamlessly integrated wireless power transfer (WPT) systems. This letter proposes a novel holographic metasurface-based WPT system tailored for EV wheels. The metasurface, with an area of 310<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ ^{2}$</tex-math></inline-formula><inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ \pi$</tex-math></inline-formula> mm<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ ^{2}$</tex-math></inline-formula>, is designed in a circular configuration to fit within the wheel structure. It consists of seven impedance levels elements, each characterized by unique surface impedances formed by ring-shaped elements. By adjusting the dimensions of these elements, the surface impedance can be precisely tuned. This configuration allows the metasurface to adhere to holographic theory, enabling precise manipulation of magnetic fields, thereby significantly enhancing transmission efficiency and range. The WPT system is integrated into a wheel model and tested, demonstrated high power transfer efficiencies of 67<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ \%$</tex-math></inline-formula> at 50 mm, 62<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> at 100 mm and 46<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> at 200 mm. This innovative approach represents a significant advancement in high-efficiency WPT for EVs.