Effective TE-Polarized Bessel-Beam Excitation for Wireless Power Transfer Near-Field Links

The possibility to establish a wireless link in the radiative near field at millimeter waves through Transverse Electric (TE) polarized Bessel beams is here investigated. Previous realizations of TE-polarized Bessel beams at millimeter waves are based on leaky-wave resonant cavities fed with loop antennas. Unfortunately, these feeders also excite undesired, nonnegligible Transverse Magnetic (TM) field components, thus leading to a hybrid TE polarization, rather than a pure TE polarization. In this work, we propose a radial-slot array feeding technique as an effective solution to generate almost pure TE-polarized Bessel beams in leaky-wave resonant cavities. The design is based on an effective leaky-wave approach for the characterization of the launcher. The proposed TE feeding scheme is validated with full-wave results. The study of a complete wireless power transfer scenario shows that the proposed solution significantly improves the link budget compared to previous hybrid TE- and TM-polarization cases.