Rectangular - to - Circular Waveguide Transformers Analysis and Design of Flange - Integrated for Splashplate Antenna Feeds

Splashplate feeds, e.g. [1], are increasingly used for high performance parabolic antennas. The feed is directly interfaced in the focus of the antenna by a straight circular waveguide through the antenna vertex which simultaneously acts as feed support. At the far side of the waveguide, the need of a circularto-rectangular waveguide transition is obvious to overcome proper interfacing with standard rectangular waveguide types commonly used for commercial transceiver equipment. The direct integration of a suitable transition design within the vertex feed support flange facilitates compactness, handling and, therefore, low overall feed system cost. As shown in Fig.1, such a concept requires design capabilities for short and compact transformers as well as the incorporation of milling radii in the cross section of the flange to account for an easy manufacturing process.