Abstract: This radiating slot array antenna is made out of a printed circuit sandwich structure with: a radiating plate in printed circuit form transparent to microwaves having, on its upper face, a metallization plane in which there are etched alignments of radiating slots; chutes made of a plastic material with a metallized inner wall, the chutes having their hollow part before the upper face of the radiating plate, being soldered by their edges to the metallization plane of the upper face of the radiating plate on and parallel to the alignments of radiating slots so as to overlap them, and reconstituting the three missing walls of waveguides whose fourth wall is constituted by the metallization plane etched with radiating slots of the upper face of the radiating plate; and an upper plate assembled on the back of the chutes to ensure the stiffness of the antenna. Its composition as a sandwich of printed circuits gives it high rigidity, great lightness and a low cost price.