Abstract: An antenna for transmission of microwave energy, has a plate with openings for receiving energy from a feeding or input waveguide connected to an energy source and for feeding the received energy to a number of antenna or output waveguides provided with one or several openings through which energy from the feeding waveguide is to be emitted. The plate on the input side is provided with tracks in which a part of the feeding waveguide, which part together with the plate forms the feeding waveguide, is fixed, and the plate on the output side is provided with a number of tracks, in each of which a part of an antenna waveguide, which part together with the plate forms the antenna waveguide. In addition both the feeding waveguide part and each antenna waveguide part have the form of an open rectangular container, the edges of which together have the same form as the corresponding tracks of the plate, and the bottom of which is provided with one or several openings.