Radiation Characteristics of Multi-horn Antenna for 21 GHz Band Variable EIRP Broadcasting Satellite

Abstract

This paper describes an onboard antenna for the 21 GHz band variable EIRP (equivalent isotropically radiated power) broadcasting satellite. This frequency band provides a large rain/vapor attenuation. For example, the atmospheric attenuation is about 10 dB for 1% of the time during the worst month in Tokyo. In order to overcome the large attenuation, a multi-beam system is studied, in which each of the beams covers a small area and the radiation power of the beam is controlled according to the atmospheric attenuation of that area. The onboard antenna is one of the key components in this system. We have developed a scale model of the multi-beam antenna. The characteristics of the antenna agree with the designed characteristics.