A broadband polyrod fed conical horn

Presents an extensive experimental study on the polyrod fed horn. Results show that only a very narrow range of polyrod/horn configurations yield the observed characteristics of constant beamwidth and gain and circular beam symmetry over a broad frequency band covering typically 8.5-15.5 GHz. Detailed analysis of the results also reveal an apparent invariance to horn flare angle, but the beamwidth is seen to depend upon both polyrod permittivity and aperture diameter. A qualitative explanation of the mode of operation is put forward in which the device is believed to be amplitude controlled, in comparison to the scalar corrugated horn of the same flare angle which is phase controlled. A modal analysis of the horn is carried out in which the predictions agree well with the data, although no obvious reason can be deduced for the broadband performance