Investigations on directivity improvement of wide flare angle conical horns using inserted metallic discs

A simple and low cost method to enhance gain of wide angle conical horns is described. The method consists of inserting disc(s) inside the horn at par ticular axial locations. investigations realised by simulation and measurem ents are reported for different flare angle horns as a function of differen t geometrical parameters and frequency. The study shows that aperture effic iency enhancement can be achieved for large flare angle horns using this co ncept, thus resulting in an increase of the directivity. The insertion of d iscs influences the impedance match. However, since the objective is to stu dy the directivity enhancement, the mismatch losses are removed from experi mental data. In practice, the horn design can incorporate a matching networ k to eliminate the problem.