Abstract: A design concept for the shaped beam antenna used in the next generation of the chinese communications satellite is given in this paper. Starting from the system requirements and boundary conditions,a method to design the antenna contour pattern,which is able to match both shapes of two service zones,in relation to two different satellite positions on orbit, is described.The problems which will arise in design,and their solutions, especially the problems about the beam forming network are presented. Finally,the optimization of the antenna substsyem of the satellite on the second orbit position has been carried out,and its performance is also pre- sented.

Key words: Communication satellite, Antenna system, Optimization, Design