The coil stray capacitance is an essential factor for high-frequency coil application, such as wireless power transfer system. In this paper, in order to calculate the planar coil stray capacitance at Megahertz frequency, the theory model has been built. Based on the basic capacitance calculation equation, the mathematical model has been deduced carefully. Then, the mathematical model has been evaluated by a series of simulation models. In the simulation part, the error of the variables of the theory model has been analyzed carefully and quantitatively. In order to verify the theory and simulation model, the verification experiment has been done. The experimental results are consistent with the simulated ones and the theory model. The experimental and simulated results indicate that the theory model of the coil stray capacitance has a satisfactory accuracy, and the model has application potential in the field of wireless power transfer.
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