Analysis And Design Of Metamaterial-based Wireless Power Transfer

Wireless power transfer(WPT),which alleviates the dependence on the wires and batteries for electrical devices,is deemed to be a promising power acquisition technology which can be applied in a variety of industries,including the emerging electric vehicles(EV),the increasingly popularized wearable technologies as well as the smart home devices.However,limited transmission distances and low transmission efficiencies are still main challenges for the WPT system.By introducing metamaterials to the WPT system,this paper studies and analyzes the metamaterial-based WPT system,aiming to find effective solutions for improving the wireless transmission performance.Firstly,this paper introduces the working mechanism of inductive power transfer(IPT)and magnetic resonant coupling(MRC)system.In parallel,the double-negative characteristics of the left-handed metamaterials and the structure of the single unit cell are briefed.The current research achievements on the metamaterial-based WPT system are analyzed in respect to the transmission efficiency,misalignment tolerance and compacting size,which provides a theoretical basis for the subsequent research on the resonant frequency of the metamaterial.Secondly,the metamaterial unit cell is described in respect to the typology and material.With the assistance of HFSS,a unit cell with Swiss Roll structure is modeled and simulated.Key parameters of the unit cell,including the metal wire width,structures and positions,the number of turns of coils,the thickness / area / material of the dielectric plate,and the number of coil layers,are analyzed to find the influencing mechanism on the resonant frequency of the metamaterial.Finally,based on the theoretical analysis of the influencing mechanism of the cell parameters on the resonant frequency,metamaterial plates with different resonant frequency are designed and fabricated.With the assistance of an impedance analyzer,the resonance frequency of the fabricated metamaterial plates is measured.The measurement results are highly consistent with the simulation results,which verify the effectiveness of the theoretical findings.A metamaterial-based WPT experimental setup is built to analyze how metamaterial with different resonant frequencies act on the performance of WPT system.It provides an important theoretical basis for the application of metamaterials in WPT systems.