A new type of X-band data transmission antenna used on CBERS-1 satellite

In consideration of poor space of mounting plan towards the Earth and some technical reasons, the shaped reflector will not be recommended to use for the CBERS-1 satellite, therefore a backfire helical antenna occupied a small space is adapted for IR-MSS data transmission antenna(DTA) on the CBERS-1 instead of the shaped reflector. The antenna´s performance and function is similar to that of the shaped reflector. The design of the antenna and its performances will be briefly described in the paper. At first, it describes the ideal coverage curve and engineering model of the coverage gain for data transmission antenna on the low-orbit satellite. The paper then gives the mathematical model of radiation of the antenna, the characteristic equation for propagation constant is developed in the section. Using complex propagation constant of the helical antenna a saddle shaped beam, whose maximum pointing at 62.5/spl deg/ has been designed. Main properties and function of IR-MSS DTA on the CBERS-1 are then briefly introduced. The antenna possesses compact structure, small size, flight weight and low cost besides the similar performance to the shaped reflector. It is also more suitable for a variety of small satellites or micro satellites.