A radial slot antenna comprising a radial waveguide, which includes an upper plate, having a centroid and an edge region and provided with a plurality of radiating apertures, formed as slots in the upper plate, which develop around the centroid. The radiating apertures are arranged to form first and second radiating regions, which are distinct and radially separated by a dwell region without radiating apertures and wherein, in the first and second radiating regions, radially adjacent radiating apertures are separated from one another by a radial distance, the dwell region having a radial width greater than the radial distances of the radiating apertures in the first and second radiating regions. The slot antenna further comprises a signal feeder for supplying am electromagnetic field to assume, in the first and second radiating regions, opposite phases, so that the electromagnetic field emitted by the slot antenna can be expressed via Bessel functions.