It is known from antenna theory and practice that directional gain, aperture area using ratio, and side lobe level of reflector antennas depend on the amplitude distribution of the field sources at the radiating aperture. The most acceptable is the U-shape of the amplitude distribution of the field sources. Besides, it is desirable that the primary feed pattern has an axis of symmetry. Several feeds types are known providing such characteristics and having simple construction and wide bandwidth: pyramidal horn with a diagonal excitation [1], flare-angle changed conical and pyramidal horns [2], flare-angle changed pyramidal horn with a diagonal excitation [3], the open end of a circular waveguide with impedance flange [4]. By now a great attention is paid to investigating polarization characteristics of such feeds.

In this paper the comparison of experimental results of the directional and polarization characteristics of the above-mentioned radiators was carried out.