Analysis of Bessel and Bessel-Gauss beams in the transition region from near to far field

Bessel-Gauss beams offer a valuable trade-off among the pros and cons of Bessel and Gaussian beams. However, the behavior of such beams in the radiative near-field and far-field regions has been so far overlooked. This paper aims to fill this gap by analyzing, through a fully vectorial approach, the transition from near to far-field distances of Bessel and Bessel-Gauss beams with different beam waists. Simple design rules for obtaining leaky-wave radiating devices able to generate these field profiles are also provided by considering, as a case study, a radially periodic printed leaky-wave antenna working at 18 GHz with an aperture radius of 23.4 cm.