Delopement of mutimode horns and wideband feed for radio telescopes

Multimode horns were developed for 8.4GHz, 22GHz, 43GHz receiver systems of ASTRO-G/VSOP-2 satellite for Space-VLBI, and for 6.7GHz of VERA 20m radio telescopes of National Astronomical Observatory in JAPAN and 25m Shanghai Radio telescope in China. Rational bandwidth of these horns in low cross polar level are 20-30%, and their thin walls without corrugation and shortened length are the best for the satellite use. Also, wideband feeds will be presented, which are now developing for SKA and VLBI2010, which is a kind of Tapered Slot Antenna or other of traveling wave antenna.