PURPOSE: To improve the F/B characteristics over a wide band by using the reactance circuit and the phase shifting cable and then designing them to the proper value in order to compensate the phase shift variation caused by the mutual interference among the radiation elements.

CONSTITUTION: The unidirectional antenna is constituted with a pair of radiation elements 1 and 2 featuring the same characteristics and distributed in opposition with space d, compounding unit 5 which compounds the signals given from elements 1 and 2, reactance circuit 8 inserted into the area between element 1 and unit 5, and phase shifting cable 4 inserted between element 2 and unit 5 each. Thus either one of the feeding phases to the radiation elements is inverted, and the output given from unit 5 is supplied to the picture reciever. In other words, circuit 8 is inserted to feeder to element 1 to secure the characteristics in that the length of cable 4 is increased relatively in the low channel. As a result, the phase variation caused by the mutual interference can be compensated, thus improving the F/B characteristics over a wide band.