Title :
The effects of subreflector diffraction on the aperture efficiency of a conventional Cassegrain antenna--An analytical approach
Author :
Kildal, Per-Simon
Author_Institution :
Norwegian Inst. of Tech., Trondheim, Norway
fDate :
11/1/1983 12:00:00 AM
Abstract :
An asymptotic theory is presented with which the reduction in aperture efficiency caused by diffraction from a subreflector edge can be calculated for any dual-reflector system. The theory is applied to conventional Cassegrain antennas, for which approximate analytical effieiency formulas are derived. These formulas show that subreflector diffraction may represent a significant efficiency loss even for subreflector diameters as large as 20 wavelengths. The formulas are used to obtain an optimum subreflector size which represents the best trade-off between losses due to subreflector diffraction and geometrical shadowing.
Keywords :
Geometrical diffraction theory; Reflector antennas, multireflector; Antenna theory; Antennas and propagation; Aperture antennas; Feeds; Geometrical optics; Optical diffraction; Physical optics; Radio astronomy; Reflector antennas; Shadow mapping;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.1983.1143161