title: Magnetic metamaterial superlens for increased range wireless power transfer.
abstract: 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.
authors.affiliation: Duke University, Department of Electrical and Computer Engineering, 130 Hudson Hall, Durham, North Carolina, 27708 USA.
authors.forename: Guy
authors.initials: G
authors.lastname: Lipworth
authors.affiliation: Duke University, Department of Electrical and Computer Engineering, 130 Hudson Hall, Durham, North Carolina, 27708 USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Ensworth
authors.affiliation: Duke University, Department of Electrical and Computer Engineering, 130 Hudson Hall, Durham, North Carolina, 27708 USA.
authors.forename: Kushal
authors.initials: K
authors.lastname: Seetharam
authors.affiliation: Duke University, Department of Electrical and Computer Engineering, 130 Hudson Hall, Durham, North Carolina, 27708 USA.
authors.forename: Da
authors.initials: D
authors.lastname: Huang
authors.affiliation: Toyota Research Institute of North America, Ann Arbor, Michigan, 48105 USA.
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Toyota Research Institute of North America, Ann Arbor, Michigan, 48105 USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Schmalenberg
authors.affiliation: Toyota Research Institute of North America, Ann Arbor, Michigan, 48105 USA.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Nomura
authors.affiliation: Duke University, Department of Electrical and Computer Engineering, 130 Hudson Hall, Durham, North Carolina, 27708 USA.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Reynolds
authors.affiliation: Duke University, Department of Electrical and Computer Engineering, 130 Hudson Hall, Durham, North Carolina, 27708 USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Smith
authors.affiliation: Duke University, Department of Electrical and Computer Engineering, 130 Hudson Hall, Durham, North Carolina, 27708 USA.
authors.forename: Yaroslav
authors.initials: Y
authors.lastname: Urzhumov