A radially periodic 2-D leaky-wave (LW) antenna is studied for the generation of zeroth-order Bessel beams within a limited spatial region and over a wide-frequency range. The antenna design is wideband and based on an annular metal strip grating placed on the top of a grounded dielectric slab, supporting a cylindrical leaky wave (CLW) with a fast backward spatial harmonic. The focusing capabilities of the relevant LW aperture fields are investigated over the considered frequency range (15-21 GHz), in conjunction with the dispersion analysis of the optimized structure, which is developed by means of an efficient in-house method of moments code. Full-wave simulations using a commercial tool including a simple coaxial feeder are presented and discussed, demonstrating the desired wideband operation. The antenna design is validated by means of measurements performed on a manufactured prototype …