A system for forming beams that are suited to a given coverage, has at least the following elements: a configuration manager, a set of modems in contact with switches, multiplexers for multiplexing the modems by group onto as many intermediate ports each corresponding to a beam, a module for forming pathways generating a number of pathways distributed about the axis of the antenna, a phase-shift module for the beams of each of the pathways, a power transposition-amplification module and at least two antennas connected to said transposition-amplification module. For the reception part, the system comprises a set of modules that are identical with the exception of the transposition-amplification module, which carries out the low-noise reception and the transposition.