ANTENNA OF WAVEGUIDE STRUCTURE AND ITS MANUFACTURE

PURPOSE:To provide an antenna of waveguide structure and its manufacture at low cost with light weight in which the transmission efficiency of a waveguide is high. CONSTITUTION:An antenna 1 of a waveguide structure is provided with a main body 2 comprising a bottom plate 3 and plural side walls 4 placed perpendicularly to the bottom plate 3 at a prescribed interval and with a radiation plate 5 fixed to a top of the side wall 4 to cover an upper opening of the main body 2 and provided with plural slits 6. A waveguide T is made up of the bottom plate 3, the side walls 3 located side by side and the radiation plate 5. Then the radiation plate 5 is fixed to the top of the main body side wall 4 by laser welding. Since a heat is concentrated on a very small spot by the laser welding, the main body 1 and the radiation plate 5 are welded by a very small amount of a welding metal 8 and distortion by the welding is less. Thus, the thickness of the side walls 4 and the radiation plate 5 is made thin.