Abstract: A short-focus microwave reflector is located a short distance away from the feed horn and is positioned to reflect the beam of microwave radiation away from the feed axis and toward a large primary reflector antenna for transmission. A conical shield extends from the feed horn to the secondary reflector, joining them together as a unit and preventing sidelobe radiation. The beam of radiation emerges from the shield through an aperture in the sidewall thereof. The short focus of the secondary reflector causes the beam to be focussed approximately at the plane of the aperture, such that the beam diameter is small and the aperture can also be small, reducing stray radiation from the shield structure. Diffraction at the edges of the aperture is reduced by a radially surrounding choke structure which further suppresses sidelobe radiation.