PURPOSE: To improve frequency utilizing efficiency, to improve the quality of communication/broadcasting by reducing interference waves and to provide the flexibility of frequency allocation for the system by providing two feeding ports at a circularly polarized wave linear radiator and providing coupling characteristics between the two feeding ports.

CONSTITUTION: Linear radiators 1-3 are respectively provided with the two feeding ports, and coupling between these two feeding ports is provided with coarse coupling characteristics. Signals at a frequency f1 distributed at a distributor 5 are supplied to the first-order radiators 1-3. As a result, cluster feed is composed of the linear radiators 1-3 and the distributor 5, and a beam at the frequency f1 of a low side lobe is formed by this cluster feed. On the other hand, the feeding ports of the linear radiators 1 and 2 not connected with the distributor 5 are connected a non-reflection termination so as to reduce reflected waves. Further, the crossover level of the linear radiator 3 can be set high since it is multicoupled with the adjacent cluster feed.