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6607193 
Journal Article 
A wideband antenna feed-a dielectric loaded hybrid mode conical horn 
Kolettis, NJ 
1970 
393-399 
INSPEC:217093 
In this paper, a novel scheme of dual mode illumination for the ordinary conical horn is presented which increases considerably, to at least 50%, the relative bandwidth (in the context defined previously) of the resulting antenna, a dielectric-loaded hybrid mode conical horn. Briefly, the structure consists of a dielectric rod of circular cross section tapered at both ends, supported by two foam-styrene rings coaxially in an ordinary conical horn. A TElldeg mode incident upon the throat of the horn transforms smoothly over the length of the respective taper into a hybrid HElldeg mode. This mode decomposes upon traversing the aperture taper into the TElldeg and TMlldeg modes that illuminate the aperture. It is readily seen that, since the two modes are in effect generated in the neighborhood of the aperture, any phase slippage between them due to travel is virtually nonexistent. Hence, a normally troublesome factor contributing to the problem of improper mode phasing is intrinsically eliminated with this scheme of illumination.