Wireless Radiative Near-Field Links through Wideband Bessel-Beam Launchers

We investigate for the first time the possibility of realizing a millimeter-wave wireless link in the radiative near-field through the coupling of two wideband Bessel-beam launchers. Such devices consist of a circular grounded dielectric slab with an annular strip grating on top and centrally fed by a coaxial cable. A launcher is designed at f=30 GHz with a lateral dimension of about 20 cm, to allow for comparison with resonant shielded loops of the same size found in the literature to realize reactive near-field links at 38 MHz. The wireless power transfer (WPT) performance of the radiative near-field link is then evaluated with full-wave simulations and compared against literature results for reactive near-field links. Results demonstrate the superior performance of the proposed radiative near-field link, thus paving the way for a new paradigm in the realization of wireless power and/or information transfer links.