Compact dual-frequency feed for prime-focus paraboloid
- 29 August 1991
- journal article
- Published by Institution of Engineering and Technology (IET) in Electronics Letters
- Vol. 27 (18) , 1682-1683
- https://doi.org/10.1049/el:19911050
Abstract
A compact dual-frequency feed operating at 1420 and 408MHz has been developed for a prime focus paraboloid. Efficient dual-mode performance at 1420MHz results from the combination of modes in a circular waveguide of diameter 0.91λ1420 and a surrounding cavity of diameter 2.611420. A single TE11 mode is excited in the larger cavity at 408MHz by four slots in its back wall, which acts as a dichroic structure, allowing the passage of 408MHz energy while reflecting 1420MHz fields. Satisfactory 408MHz performance is obtained in a feed of depth only 0.55λ408, without significant effect on 1420MHz performance.Keywords
This publication has 0 references indexed in Scilit: