A transmit-array collimating assembly, this collimating assembly being able to convert a first electromagnetic wave radiated from a first focal point and in a first frequency band, into a plane electromagnetic wave of same frequency radiated in a preset first direction, and to convert a second electromagnetic wave radiated from a second focal point and in a second frequency band, into a plane electromagnetic wave of same frequency radiated in the same preset first direction, first and second primary radiating elements solely connected to first and second output ports of a transmitting module, respectively. The first and second primary radiating elements are positioned so as to radiate the first and second electromagnetic waves from the first and second focal points, respectively.