A prototype of a simple monopulse feed for the primary focus of a deep symmetric parabolic antenna with a f/d ratio of 0.4 covering the frequency band of 2,25GHz is optimized in this work. The feed consists of a patch radiator for the sum and a monopole for the difference signal in a circular cavity. As the sum mode is left-hand circularly polarized, both antenna and receiver can be simplified even in the case of two dimensional tracking. First the related area is overviewed, followed by a theoretical introduction needed for the feed analysis and optimization. After the original-prototype analysis, a suitable computer-simulation program is selected. The original prototype is then adequately modelled and optimized by parametric simulations with the chosen program HFSS. Finally a new prototype is designed, built, measured and compared with the original one. Setting the beamwidth for even deeper parabolic dishes is also presented in the results.
|