Efficient small reflector with hat feed

The hat feed is a new axially self-supported feed for a single-reflector antenna. The advantage of it is that the outer surface of the axial waveguide is used as a desired radiating element, and thereby it does not cause an undesired blocking of the aperture like in other self-supported feeds. The authors present a hat feed at 15 GHz in a deep reflector with 43 cm diameter. The reflector is so deep that a plane radome can be mounted across the aperture. The antenna efficiency including mismatch is larger than 60% over a 6% bandwidth, and the sidelobes are extremely low