Magnetic metamaterial superlens for increased range wireless power transfer

• Published in: Scientific reports Vol. 4; no. 1; p. 3642
• Main Authors: Lipworth, Guy, Ensworth, Joshua, Seetharam, Kushal, Huang, Da, Lee, Jae Seung, Schmalenberg, Paul, Nomura, Tsuyoshi, Reynolds, Matthew S, Smith, David R, Urzhumov, Yaroslav
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 10.01.2014
• Subjects: Aperture; Efficiency; Energy conservation; Magnetic fields; Permeability
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep03642

The ability to wirelessly power electrical devices is becoming of greater urgency as a component of energy conservation and sustainability efforts. Due to health and safety concerns, most wireless power transfer (WPT) schemes utilize very low frequency, quasi-static, magnetic fields; power transfer occurs via magneto-inductive (MI) coupling between conducting loops serving as transmitter and receiver. At the "long range" regime - referring to distances larger than the diameter of the largest loop - WPT efficiency in free space falls off as (1/d)(6); power loss quickly approaches 100% and limits practical implementations of WPT to relatively tight distances between power source and device. A "superlens", however, can concentrate the magnetic near fields of a source. Here, we demonstrate the impact of a magnetic metamaterial (MM) superlens on long-range near-field WPT, quantitatively confirming in simulation and measurement at 13-16 MHz the conditions under which the superlens can enhance power transfer efficiency compared to the lens-less free-space system.