Efficient modeling of the wireless power transfer efficiency for varying positions and orientations between transmitter and receiver

A method that efficiently calculates the Power Transfer Efficiency (PTE) of a Wireless Power Transfer (WPT) system is described in this paper. It allows for arbitrary relative positions and orientations between devices in the system, both in far-field and radiative near-field configurations. The method uses a single simulation or measurement of the radiation patterns of the antennas employed in the WPT system, from which the interaction between devices at any relative position and orientation can be modeled. A spherical harmonics decomposition, together with Wigner-D rotation matrices, is applied to perform efficient translations and rotations of the devices used in the WPT system.