A new low noise, high gain antenna

A new antenna type is described which combines the low noise temperature characteristics of the horn-reflector antenna with the more attractive mechanical features associated with the paraboloidal reflector. Cassegrain optics used in an off-set feed configuration enables a virtual source to be formed without sub-reflector blockage. An extremely compact structure is realized with a concave hyperboloid which mirrors the actual feed located on the paraboloidal surface. Except for the aperture, the antenna is completely shielded. The design approach is outlined and measurements on an experimental model are presented. Ground noise contribution from minor lobes is about K.