Method of producing a horn antenna array and antenna array

A method of producing a horn antenna,

• each horn antenna including
• a horn, and
• a base having a slot extending along a second direction which intersects the first direction, the base closing the horn at one end,
• the horn including
• a pair of electrically-conductive first inner walls each intersecting the first direction,
• a pair of electrically-conductive second inner walls each intersecting the second direction, and
• a bridge being continuous with the pair of second inner walls and extending along the second direction, the bridge having two electrically conductive faces respectively opposing the pair of first inner walls,
• the production method of the horn antenna comprising:
• providing a first die and a second die;
• assembling the first and second dies, filling an internal space surrounded by the first and second dies with a fluid material, and solidifying the fluid material;
• and,
• after the material has solidified, separating the first and second dies and retrieving a molding therefrom, wherein,
• in a portion corresponding to each horn antenna element, the first die has a pair of protrusions and a groove between the pair of protrusions;
• in a portion corresponding to each horn antenna element, the second die has a protrusion;
• and,
• in a state where the first and second dies are assembled,
• at least a portion of the protrusion of the second die is located in the groove of the first die, and
• a gap exists between a tip end of the protrusion of the second die and a bottom face of the groove of the first die,
• wherein,
• the bottom face of the groove of the first die defines a front-side surface of the bridge of the horn of each horn antenna element;
• two side faces which are continuous with the bottom face of the groove of the first die define the two electrically conductive faces of the bridge;
• portions of the surface of the pair of protrusions of the first die define the pair of first inner walls of the horn;
• and
• a tip-end surface of the protrusion of the second die defines a rear-side surface of the bridge.