| 摘要 |
PURPOSE:To prevent service interruption of a radio line by constituting an array antenna with plural circular conductor discs in parallel with a ground conductor board and changing over a switch of a feeding system at abnormality so as to shape a specific beam. CONSTITUTION:The circular conductor discs provided within a plane in parallel with the ground conductor board 1 are used as element antennas 2-7 and constitute the array antenna. Coaxial cables with different length are used as fixed phase shifters 23-29 of the feeding system, and when arranging intervals d1, d2 of the antennas 2-7, the exciting phase amount to be given to the antennas 2-7 is decided in order to form each radiation beam irradiated from the antennas (forward/backward/left/right direction beams used normally and a four-leaf beam directed in forward/backward/left/right directions used in abnormality). Then switches 11-22 are thrown to the position A at the abnormality of a power supply to obtain the four-leaf beam directed four (forward/backward/left/right) directions depending on the operation of the antennas 2, 5, 6, the resulting beam is close nearly to the nondirectivity and the communication with each base station is attained. |
