Recent advances on elliptical-beamshape horns

The crosspolar performance of horn antennas with elliptical beams, operated in dual linear or circular polarization, is discussed. Rectangular and elliptical horns based on the dielectric core approach have been designed and measured. Only linearly polarized patterns need to be measured to determine the performance when the horn is operated in circular polarization, assuming that other crosspolar sources are small. It is shown that the simple dielectric core horns potentially have a much larger crosspolar bandwidth than their corrugated counterparts (probably more than 30%). They also represent a much cheaper design. The horn approach is very critical to tolerances on the alignment of the dielectric core inside the horn and has a large mass of low frequencies. The elliptical horn exhibited lower sidelobes than the rectangular horn, which makes it more efficient for illuminating an elliptical reflector.<>