| 摘要 |
PROBLEM TO BE SOLVED: To secure isolation of a transmission antenna from a reception antenna in a relay station, and to improve the productivity of the relay station. SOLUTION: The transmission antenna 10 has two 2L antenna elements 1, 2 forming two loop antenna elements; a feeder 4 for transferring powers to the respective 2L antenna elements 1, 2; and each coaxial tube 3 branching off in two direction from the feeder 4, and being interposed in between each 2L antenna element 1, (2) and the feeder 4, and having each branching end connected directly with the feeding point of each 2L antenna element 1, (2) whose characteristic impedance is twice as large as the one of the feeder 4 and is nearly equal to one of each 2L antenna element 1, (2). Further, distances L1, (L2), (L3) are set toλ/2, which are in between each pair of adjacent loops included in the loops arranged in a vertical direction A1 which constitute the respective 2L antenna elements 1, 2 to form the null point of the directivity of the transmitting antenna 10 in the vertical direction A1.
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