The three-dimensional vector diffraction problem of radiation of two parallel halfwave length vibrators on infinitely thin perfectly conducting screen with square form is solved within the frame of the uniform geometric theory of diffraction method. The results of calculation have shown that at placement of the vibrators at distance between them x = 0.42–0.55l at height h = 0.25l above the square screen with the side size L = 1–2l it is possible to provide identical width of the main lobe of patterns in the Н- and E- observation planes, 2DqН = 2DqE. At distance x = 0.5l the maximum power gain in the normal direction to the screen equals 6.6, when the screen side size L = 1.3l, and the condition DqН = DqE is carried out to the field level –25 dB. The radiation resistance values do not depend on the screen side size since the size screen equals to wave length.