Reflector (antenna)

Any gain-degrading factors which raise side lobes have a two-fold effect, in that they contribute to system noise temperature in addition to reducing gain.

The standard symmetrical, parabolic, Cassegrain reflector system is very popular in practice because it allows minimum feeder length to the terminal equipment.

Note however that the asymmetry can have deleterious effects on some aspects of the antenna's performance - for example, inferior side-lobe levels, beam squint, poor cross-polar response, etc.

Note that in the case of a front-fed Cassegrain the feed horn and feeder (usually waveguide) need to be covered with an edge absorber in addition to the circumference of the main paraboloid.

Measurements are made on reflector antennas to establish important performance indicators such as the gain and sidelobe levels.