Figures-of-Merit for Wireless Power Transfer

Recently, the field of wireless power transfer (WPT) has seen significant advances and general interest. This paper attempts to contribute by providing figures-of-merit that enable an easy and universally applicable formula for comparing such systems. This is done by taking into account the systems’ physical dimensions, when compared to the wavelength, and the beam efficiency. Although initially designed for radiative scenarios, the results presented here can be applied both to radiative and coupling WPT. The present discussion includes the derivation, exploration of the various parameters and application to several systems found in the literature.