Title :
Imaging in a Gregorian antenna from 12 to 30 GHz
Author :
Dragone, Corrado ; Ruscio, J.T.
Author_Institution :
AT&T Bell Labs., Holmdel, NJ, USA
fDate :
2/1/1988 12:00:00 AM
Abstract :
A Gregorian antenna with the main reflector illuminated by magnified image of a small horn aperture was built and tested from 12 to 30 GHz. The image is approximately frequency-independent, and the main reflector is illuminated with negligible spillover. Polarization distortion caused by aberration is very small, in excellent agreement with a simple expression derived previously by the author (ibid., March 1987). Spatial filtering by the subreflector causes the far-field sidelobes in the principal plane orthogonal to the symmetry plane to be very low, about 80 dB below the main beam at 16.5 GHz for angles from the axis that are greater than 20°
Keywords :
antenna radiation patterns; antenna reflectors; reflector antennas; 12 to 30 GHz; 16.5 GHz; 80 dB; Gregorian antenna; SHF; far-field sidelobes; magnified image; main reflector; polarisation distortion; small horn aperture; spatial filtering; subreflector; Antenna measurements; Aperture antennas; Ellipsoids; Filtering; Frequency; Horn antennas; Optical filters; Optical imaging; Polarization; Reflector antennas;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
