A lucid design criterion for wireless power transfer systems to enhance their maximum available efficiency

This paper considers a two-port black box representing wireless power transfer systems. We regard the port voltages as independent variables, and formulate the input and output effective powers as scalar functions of the voltages and admittance parameters for the system. Jacobean determinant zero finds the optimum voltage set that makes the power transfer efficiency reach its peak. We derive a maximum available efficiency expression in terms of a heuristically introduced angular parameter. In contrast to conventional kQ, the angular parameter can be calculated from just admittance matrix without concerning coupled resonance. Double angle tangent works as a useful figure of merit for wireless power transfer systems.