| 摘要 |
PURPOSE:To improve the radiation characteristics of an antenna by fixing the diameter of a through hole provided to a subreflector so as to make a part of radio waves pass through the hole. CONSTITUTION:The greater part of radio waves radiated from a primary radiator 4 is reflected by the subreflector 2 and a main reflector 1 to form a radio wave 5 running in the main beam direction. A part of the radio waves radiated from the radiator 4 is passed through the through hole 3 to form a radio wave 6 running in a specific direction. If the wall surface of the hole 3 is constituted by a conductive material such as a metal and the diameter of the hole 3 is set up so as to be excluded from the interrupting area of the radiated radio waves, the hole 3 acts as a kind of a waveguide and the radio wave passing through the waveguide changes its phase larger as compared with free space. Therefore, a side lobe in the required direction can be lowered without using a specific device and the size and weight of the antenna can be reduced. |
