Analysis and experimental results for an inductively coupled near-field power transmission system

An inductively coupled near-field wireless power transmission system, consisting of transmitter and receiver coils connected via appropriate impedance matching network to source and load respectively, is analyzed to address how the properties of antennas and impedance terminations impact on the performance of such a system. This is achieved by deriving the power transfer relationship of inductively coupled resonant loops based on their equivalent circuit model. It leads to a concise formulation called near-field power transfer equation, which expresses the transferred power as a function of dimensions and intrinsic quality factors of the loops, distance between the loops, and terminating impedances at both the transmitter and the receiver. Experimental results validate the derived near-field power transfer expression.