Bessel-Gauss Beam Launchers for Wireless Power Transfer

In this work, we study the use of Bessel-Gauss beam launchers for wireless power transfer (WPT) applications. The power transfer efficiency between two radiating apertures is investigated in the radiative near field. A spectral Green's function approach is used to derive the power efficiency under a simultaneous conjugate impedance match. The transverse electromagnetic (TEM) mode of a coaxial cable, as well as Bessel beam (BB) and Bessel-Gauss beam (BGB) field distributions, are considered as aperture distributions. Numerical results demonstrate that a BGB field distribution is the optimal choice for WPT due to its limited spectrum and reduced diffraction of the radiated beam. We synthesized a Bessel-Gauss launcher that exhibits power efficiency exceeding 50% for distances larger than 30λ. These results show that non-diffracting beams can pave the way toward efficient near-field WPT systems with extended operating ranges.