ARMY ELECTRONICS COMMAND FORT MONMOUTH NJ
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The report describes the development of two very broadband horn antennas using double-ridged waveguide techniques. The first design accomplished was that of a feed horn to be used to illuminate a six-foot parabolic reflector over the frequency range from 1 GHz to 12 GHz. Pattern data show that the beamwidth of this horn design rapidly becomes narrower than would normally be considered acceptable for that purpose. However, that was considered to be useful for the intended application since it was required that the half-power beamwidth from the six-foot parabola not become less than two degrees. That indicates that only one half of the reflector should be illuminated at the upper frequency limit. The second development consisted of designing a larger horn with a nominal gain of approximately 15 db and with a significant requirement that the gain variation be held to a minimum over the frequency range. The technique used to reduce the gain variation consisted of using relatively large flare angles to introduce increasingly greater phase error with increasing frequency and thus reduce the aperture efficiency. Electrical performance characteristics are presented for the two horn designs as well as data measured with the feed horn illuminating a six-foot parabolic reflector.
- Electrical and Electronic Equipment