2018 Volume E101.B Issue 7 Pages 1708-1715
The impedance expansion method (IEM), which has been previously proposed by the authors, is a circuit-modeling technique for electrically-very-small devices. This paper provides a new idea on the principle of undesired radiation in wireless power transfer systems by employing IEM. In particular, it is shown that the undesired radiation is due to equivalent infinitesimal dipoles and loops of the currents on the coils.