In this work, we investigate the propagation of magneto-inductive waves (MIWs) in ordering magnetic metamaterial (MM) structures. The proposed non-homogeneous MM slab consists of 9 × 9 MM unit cells constructed from a five-turn spiral embedded on an FR-4 substrate. External capacitors with the value of 40 pF or 50 pF were added to control the resonant frequency of each unit cell in accordance with the waveguide configurations. The characteristics of metamaterial structures, such as negative permeability, current ratio, transmission response, and field distribution in the waveguide, have been thoroughly analyzed by simulation and experiment. Because of the strong magnetic field confinement in the waveguide, the transmittance after nine elements of the non-homogeneous MM slab is 5.2 times greater than that of the homogeneous MM slab. This structure can be applied to the planar near-field wireless power transfer, position sensor, and low-frequency communication.

Recently, wireless power transfer (WPT) has been a topic of interest due to its attractive applications in modern life. Starting from Tesla’s idea about a century ago, WPT has developed tremendously and appeared in many of the most modern electronic devices. However, some WPT systems still have limitations such as short transmission distance, low transfer efficiency, and electromagnetic leakage. Magnetic metamaterial (MM) is a potential candidate that can overcome the above disadvantages of WPT. This paper is intended to present an overview of recent advances and research progress on WPT systems. Three classes of WPT consisting of short-range, mid-range, and long-range, will be analyzed in detail both in terms of fundamentals and applications. Especially, MM configurations can be used to enhance the near-field WPT efficiency and reduce the leakage of electromagnetic field will also be evaluated. This article is expected to provide a comprehensive review of the mechanism and applications as well as the future development of metamaterial-based WPT systems.