We describe efficient four-coil inductive power transfer (IPT) systems that operate at 100 MHz. The magnetically coupled transmitter and receiver were made from electrically small and high- ${Q}$ loop-gap resonators (LGRs). In contrast to the commonly used helical and spiral resonators, the LGR design has the distinct advantage that electric fields are strongly confined to the capacitive gap of the resonator. With negligible fringing electric fields in the surrounding space, the IPT system is immune to interference from nearby dielectric objects, even when they are in close proximity to the transmitter and/or receiver. We experimented with both cylindrical and split-toroidal LGR (TLGR) geometries. Although both systems performed well under laboratory conditions, the toroidal geometry has the additional advantage that the magnetic flux is weak everywhere except within the bore of the LGR and in the space directly between the transmitter and the receiver. Furthermore, we show that the TLGR system can be operated efficiently at a fixed frequency for a wide range of transmitter–receiver distances. The experimental results are complimented by 3-D finite-element simulations that were used to investigate the electromagnetic field profiles and surface current density distributions. Finally, we demonstrate the use of our IPT system at powers up to 32 W and discuss possible applications.

中文翻译：

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使用磁耦合环隙谐振器以 100 MHz 进行中档无线功率传输

我们描述了在 100 MHz 下运行的高效四线圈感应功率传输 (IPT) 系统。磁耦合发射器和接收器由电学上小而高的材料制成 ${Q}$ 环隙谐振器 (LGR)。与常用的螺旋和螺旋谐振器相比，LGR 设计具有明显的优势，即电场被强烈限制在谐振器的电容间隙内。由于周围空间中的边缘电场可以忽略不计，IPT 系统不受附近介电物体的干扰，即使它们非常靠近发射器和/或接收器。我们对圆柱形和分裂环面 LGR (TLGR) 几何结构进行了试验。虽然这两个系统在实验室条件下都表现良好，但环形几何结构还有一个额外的优势，即除了 LGR 的孔内和发射器和接收器直接之间的空间外，其他任何地方的磁通量都很弱。此外，我们表明 TLGR 系统可以在固定频率下有效运行，适用于广泛的发射器 - 接收器距离。实验结果得到了用于研究电磁场分布和表面电流密度分布的 3-D 有限元模拟的补充。最后，我们演示了功率高达 32 W 的 IPT 系统的使用，并讨论了可能的应用。