Abstract
For 21-GHz band satellite broadcasting system, we are studying a 300-MHz class wide band transponder. It is approximately 8 times as wide as that applied in 12-GHz band broadcasting satellite. Therefore, it is required higher power for both feeder- and down-link transmitter comparing with the conventional one for 12-GHz band broadcasting satellite. In order to avoid an extremely huge output power transmitter or an enormously giant reflector antenna for the earth station, we studied a high-gain feeder-link receiving antenna assuming the aperture diameter of 1.8m and the design frequency of 18 GHz.
