A knob placed at the vertex of a subreflector to reduce subreflector mismatch in a shaped Cassegrain antenna can significantly degrade the radiation pattern and reduce efficiency. A practical procedure is described to lessen these effects. Best results are obtained using a cosine-squared-shaped knob, keeping a low knob height and knob base within the feed blockage region. The importance of simultaneously optimising for return loss, antenna efficiency and sidelobe level is emphasised.
|Number of pages||2|
|Publication status||Published - 25 Apr 1996|
- Antenna feeds
- Antenna radiation patterns