Cassegrain Antenna 26.5-40GHz Frequency Range, Gain 40dBi Typ.RM-CGA28-40

A Cassegrain antenna is a highly efficient dual-reflector antenna, whose name and design are derived from the Cassegrain telescope. It consists of a primary reflector (a paraboloid) and a secondary reflector (a hyperboloid), positioned above the focal point of the primary reflector.

Its operating principle is as follows: the feed horn initially radiates electromagnetic waves towards the secondary reflector, which then reflects the waves onto the primary reflector. The primary reflector collimates these waves into a parallel, highly directional beam for transmission. This “folded” optical path allows the feed to be mounted behind the primary reflector, significantly reducing feedline loss and simplifying maintenance.

The key advantages of this antenna are its high gain, low side lobes, compact structure (compared to a long-focal-length parabola), and the placement of the feed and receivers behind the primary reflector, which minimizes transmission loss. Its main disadvantage is the blockage of part of the main beam by the secondary reflector and its support structure. It is widely used in satellite communications, radio astronomy, and long-range radar systems.