Array antenna having: a. a first plate, which has a wave guide structure for distributing an electromagnetic signal to be emitted by the array antenna, b. a second plate which has first openings for through-conducting the electromagnetic signal to be emitted, and c. a third plate which has means for emitting the electromagnetic signal, wherein d. the second plate is arranged between the first and the third plate (2, 4), is operatively connected thereto, and the second plate has two essentially coplanar, undented lateral surfaces (5, 6) in which the first openings are arranged, e. the first and/or the third plate (2, 4) are made of plastic which is at least partially electrically conductively coated, f. the plates (2, 3, 4) are operatively connected to one another by gluing, soldering or welding in such a way that a continuous contact between the plates is ensured along the wave guide structures, and g. the third plate has horn-shaped openings for emitting the electromagnetic signal, wherein four horn-shaped openings are each commonly operatively connected to a first opening in the second plate by a connecting duct arranged on the rear side of the third plate and are operatively connected via the first opening with the wave guide structure arranged in the first plate, h. wherein the first plate has a distributor tree which is formed of H-shaped, branched, duct-like recesses, and the ends of the duct-like recesses correspond to the first openings, i. wherein the second plate is designed so that compared with the first plate and the third plate it has a higher mechanical stability and thus determines the shape of the overall array antenna geometry. a. a first plate, which has a wave guide structure for distributing an electromagnetic signal to be emitted by the array antenna, b. a second plate which has first openings for through-conducting the electromagnetic signal to be emitted, and c. a third plate which has means for emitting the electromagnetic signal, wherein d. the second plate is arranged between the first and the third plate (2, 4), is operatively connected thereto, and the second plate has two essentially coplanar, undented lateral surfaces (5, 6) in which the first openings are arranged, e. the first and/or the third plate (2, 4) are made of plastic which is at least partially electrically conductively coated, f. the plates (2, 3, 4) are operatively connected to one another by gluing, soldering or welding in such a way that a continuous contact between the plates is ensured along the wave guide structures, and g. the third plate has horn-shaped openings for emitting the electromagnetic signal, wherein four horn-shaped openings are each commonly operatively connected to a first opening in the second plate by a connecting duct arranged on the rear side of the third plate and are operatively connected via the first opening with the wave guide structure arranged in the first plate, h. wherein the first plate has a distributor tree which is formed of H-shaped, branched, duct-like recesses, and the ends of the duct-like recesses correspond to the first openings, i. wherein the second plate is designed so that compared with the first plate and the third plate it has a higher mechanical stability and thus determines the shape of the overall array antenna geometry.