The present invention provides an antenna comprising at least two arrays comprising respective pluralities of radiating elements in alignment, disposed in parallel planes, and metal screens interposed between the arrays, the antenna being characterized in that each metal screen comprises a bottom portion facing non-radiating portions of the radiating elements and comprising respective plane sheets disposed in planes parallel to the planes of the arrays, and top portions facing the radiating portions of the radiating elements and comprising panels, each forming an angle with the planes of the bottom portions. Preferably, each panel is oriented in alternation in one direction and in another direction on either side of the plane of the bottom portion. Advantageously, each panel comprises two wings connected to a central zone attached to the bottom portion of the screen.