Low-noise dual-hybrid-mode-horn--an experimental model.

This paper presents a detailed description of an experimental corrugated feed horn designed to operate at the focus of a paraboloidal reflector. It is found that the corrugation depth does not critically restrict the bandwidth of the antenna, and the main requirement is that the thickness of the corrugation teeth must be small compared to the wavelength. The radiation pattern of the horn maintains a near-perfect cylindrical symmetry over a 10% bandwidth, and the V.S.W.R. is less than 1-1 within the same bandwidth. The overall efficiency of the antenna system is found to be within 3% of the maximum value predicted by the theory. In addition, the spill-over loss is very small, and is of the order of 3.5%. This indicates that a low-noise, high-efficiency antenna can be designed without the need of a massive and more costly conical horn used in dual-reflector systems to date. [ABSTRACT FROM AUTHOR]