Space-qualifying a lightweight corrugated horn with low sidelobes for global Earth coverage

This paper describes the testing of a lightweight compact multimode corrugated horn with low sidelobes, which are <-36 dB, for global Earth coverage from a geostationary orbit. We have previously presented an initial study and results from the testing of a prototype aluminium horn (see Granet, C. et al., IEEE Trans. Antennas and Propagat., vol.48, p.1125-33, 2000; IEEE Antennas and Propagation Society Symposium, p.712-15, 1999). We also presented the manufacture from composite materials and a theoretical mechanical and thermal analysis of the lightweight horn (see Bird, T.S. et al., AP2000 Millennium Conference on Antennas and Propagat., paper 0085, 2000). This latter horn was fabricated from carbon fibre reinforced plastic (CFRP) materials by Composite Optics Inc. (COI, San Diego, USA) and has a mass of only 9.3 kg, which is an order of magnitude reduction when compared to the 110 kg of the aluminium prototype horn. The CFRP was plated with copper on the interior of the horn to increase the electrical conductivity. As the horn is intended for space flight, a number of tests were carried out for space qualification purposes. We report the results of these tests.