Abstract: An antenna includes a disk of dielectric material with a number of radiator elements and signal processing circuits. The radiator elements are arranged mirror-symmetrically with respect to two perpendicular axis and are divided into a number of sectors. When the antenna is a receiver a first part of the signal processing circuits is arranged in a first layer of the disk for combining signals emitted by the elements of any sector while a. A second part of the signal processing circuits is arranged in a second layer of the disk for combining signals coming from sectors similarly located with respect to the axes to groups of signals, each group of signals having at least one signal of generated sum signals and difference signals with respect to the two axes. A third and last part of the signal processing circuits is arranged in a third layer of the disk for combining in the groups of signals included sum signals and difference signals and for emitting the combined signals to the output terminals of the antenna.