ELECTRIC WAVE MASKING SUBSTANCE

摘要

PURPOSE:To improve the front/back radiation ratio, by attaching at the periphery of an aperture the two sets of electric wave masking substances having the same sum of the lengths in the circumferential direction and different lengths in the direction of rotating axle. CONSTITUTION:The electric masking substance consists of a reflector 1, the primary radiator 2 plus two sets of electric wave masking plates 3a and 3b. The plates 3a and 3b are reduced as less as possible in terms of the rim 6 that is parallel to the rotating axle 5 and also connected together in the direction having 45 deg. to the horizontal surface 8 with a length equal to that along the rotating axle of the masking plate. A good wide-angle radiation characteristics is required especially within the horizontal surface for an antenna which is used to the ground circuit or the like. In this connection, the length along the axle 5 is set longer for the plate 3b within the horizontal surface 8 than the plate 3a within the vertical surface 7.