Title :
Characteristics and design of the LAR offset system with feed-reflector
Author :
Mousavi, Pedram ; Shafai, Lotfollah ; Veidt, Bruce ; Daneshmand, Mojgan ; Dewdney, Peter
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Manitoba, Winnipeg, Man., Canada
fDate :
7/1/2003 12:00:00 AM
Abstract :
A novel approach for analyzing the quasi-optical offset large adaptive reflector (LAR) Cassegrain system is described. In this system, a feed-reflector is used to illuminate a reconformable hyperboloid subreflector with 5-10 m diameter, located 500 m above the ground. An exact equation for the offset LAR surface is given. To scan the beam up to 60° which is one of the LAR requirements, the concept of the dual offset LAR with feed-reflector is introduced. In this design, the cross polarization is eliminated by a proper orientation of the subreflector. The parameters of the configuration are obtained by utilizing generalized Gauss-Laguerre beam modes and matrix representation of the beam mode transformation factor. The blockage effect due to the feed-reflector is totally removed.
Keywords :
antenna radiation patterns; antenna theory; electromagnetic wave polarisation; matrix algebra; offset reflector antennas; radioastronomy; radiotelescopes; reflector antenna feeds; scanning antennas; 2 to 22 GHz; 5 to 10 m; 500 m; Cassegrain system; Gauss-Laguerre beam modes; Gaussian beam; antenna radiation patterns; beam scanning; cross polarization; dual offset reflector; feed-reflector; hyperboloid subreflector; large adaptive reflector; matrix representation; quasi-optical offset reflector; radio astronomers; radio telescope; reconformable subreflector; Actuators; Antenna feeds; Antenna radiation patterns; Apertures; Equations; Gaussian processes; Optical receivers; Polarization; Reflector antennas; Shape control;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2003.813634
