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Vol . 8      No. 2    April  2000

Cassegrain Antenna System

Cassegrain antenna is a double reflector system which works on the principle of tfapr17.jpg (10527 bytes)cassegrain optical telescope. It employs a parabolic contour for the main dish and a hyperbolic contour for the sub dish. One of the two foci of the hyperbola is the real focal points of the system and is located at the center of the feed; the other is a virtual focal point which is located at the focus of the parabola. Cassegrain antenna permits a reduction in the axial dimensions of the antenna just as in optics and also permits greater flexibility in the design of the feed system.

Cassegrain geometry allows placement of the RF plumbing behind the reflector which eliminates the need for long transmission lines. A high gain cassegrain reflector antenna in Ku-band has beer successfully developed for command transmit application for the missile programme. It can also be used for monopulse radar, satellite communication, etc.