Cassegrain Antenna


Also found in: Wikipedia.

Cassegrain antenna

[kas·gran an′ten·ə]
(electromagnetism)
A microwave antenna in which the feed radiator is mounted at or near the surface of the main reflector and aimed at a mirror at the focus; energy from the feed first illuminates the mirror, then spreads outward to illuminate the main reflector.

Cassegrain Antenna

 

(named for the 17th-century French physicist N. Cassegrain), a reflecting antenna that consists of a radiator and primary and secondary (auxiliary) electromagnetic energy reflectors (mirrors) assembled according to the scheme of a Cassegrain telescope. The Cassegrain antenna is widely used in radio communications, radar, and radio astronomy in the centimeter wavelength band.

The primary reflector, which is a paraboloid of revolution, determines the width of the directivity pattern of the Cassegrain antenna and forms a plane front of the radiated electromagnetic wave. A radiator, usually a horn, dielectric, helical, or dipole antenna, is located at the vertex of the primary reflector; such an arrangement significantly reduces the length of the lines feeding energy from the transmitter to the radiator. The auxiliary reflector, of smaller diameter, is a hyperboloid of revolution, one focus of which coincides with the focus of the primary reflector, and the second with the phase center of the radiator. A radiator with a directivity pattern of special shape and a low level of fringe radiation is used to reduce the dissipation of electromagnetic energy beyond the edges of the auxiliary reflector.

O. N. TERESHIN and G. K. GALIMOV

Mentioned in ?
References in periodicals archive ?
The mission requires a conventional Cassegrain antenna structure, with the main reflector a circular symmetric surface, while the sub-reflector a shaped one.
Gaussian type distribution is a good approximation in many systems, such as the output field of a Cassegrain antenna.
The reason for choosing this range for a is that (1) for a conventional Cassegrain antenna, the focus of the hyperboloidal reflector has to be coincide with that of the paraboloidal reflector, which requires that the vertex of the hyperboloidal reflector lays between the two foci of the hyperboloidal reflector (a < 1); and (2) The vertexes of the two branch of the hyperboloidal reflector have to be separate with each other (0.
Casey, "A C/X/Ku-band dual polarized Cassegrain antenna system," IEEE Antennas and Propagation Society International Symposium, Vol.
The method used for deriving the large-scale errors of the Centro Astronomico de Yebes (CAY) 14 m Cassegrain antenna main reflector from measurements of the power radiation pattern at an elevation of 40 [degrees] is presented in this article as well as a method for correcting these errors by simple modifications on the secondary reflector.
An inexpensive and quick method to correct for the phase front distortions in the aperture field caused by the main mirror deformations in a large Cassegrain antenna has been presented.
Finally, results from a parametric trade of a Cassegrain antenna with feed and subreflector embedded in a dielectric are demonstrated.
The compact Cassegrain antenna, shown in Figure 6, was developed to receive direct broadcast satellite signals.
The sensor comprises a high/low gain Cassegrain antenna, a quasi-optical multiplexer and cooled receivers covering frequencies from 30 to 110 GHz in eight 10 GHz wide channels.
The wideband beam is focused by the Cassegrain antenna to a beam waist, which is above the plane of the GOMUX.
Beam patterns and gain were measured with a 45|degrees~ splash plate mounted above the Cassegrain antenna and multiplexer.
Srikanth, "Comparison of Spillover Loss of Offset Gregorian and Cassegrain Antennas," IEEE Antennas Propagation Soc.