BesselBeam Antennas

The capability of controlling the spatial broadening of the radiation moving away from the relevant sources is considered a very attractive feature for a plethora of applications, such as imaging, diagnostic, and wireless power transfer. An important class of ideal solutions of the scalar wave equation that remain confined and do not undergo diffracting spreading are the so-called Bessel beams. In the past few decades, several techniques have been proposed to design zeroth- and higher order Bessel beams, all based on the scalar wave theory. More recently, a significant amount of research activity has been devoted to design devices and techniques for the generation of Bessel beams at lower frequencies, thus based on conventional vector solutions of Maxwell's equation. A comprehensive review of the most representative approaches constitutes the main goal of this article.