Highly efficient wireless power transfer using metamaterial slab with zero refractive property

• Published in: Electronics letters 2014-07, Vol.50 (16), p.1158-1160
• Main Authors: Kim, Hyoungjun, Seo, Chulhun
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Coiling; coils; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; frequency 6.78 MHz; Grounds; inductive power transmission; lumped element; magnetic field focusing; Magnetic fields; metamaterial slab; Metamaterials; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Power electronics, energy conversion and sustainability; Power transfer; radiation loss reduction; Resonant frequencies; resonant frequency; Slabs; spiral structure; Transmission; transmitting coil; wireless power transfer; zero refractive property
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2014.1596

A highly efficient wireless power transfer using a metamaterial slab with a zero refractive property is proposed. The proposed metamaterial slab consists of a spiral structure, a lumped element and a via through the ground. A prototype of a wireless power transfer system and a metamaterial slab was designed and fabricated. Experiment results prove the transfer efficiency improvement with the proposed metamaterial slab. The power transfer efficiency is improved by reducing the radiation loss through focusing the magnetic field. The power transfer efficiency is above 45% at a distance of 100–150 mm, and the resonant frequency is 6.78 MHz. The sizes of the transmitting coil and the metamaterial slab are 140 × 210 mm and 50 × 70 mm, respectively.