| 摘要 |
PROBLEM TO BE SOLVED: To realize excellent horizontal surface omnidirectivity over the entire frequency bands, even if a plurality systems of antenna units are arranged at positions of the same height around a column. SOLUTION: Two systems of antenna units 2, 3 are arranged around a steel tower so as to form nearly a cylinder or an equilateral polygon, and the units are set so as to have horizontal surface omnidirectivity by multi-surface composition for each system . The antenna units 2, 3 have different set frequencies f1, f2, and are alternately arranged with different arrangement dimensions D1, D2 around the tower so as to have the same angleθ. In this case, the set frequency f1 of the first antenna unit 2 is lower than the set frequency f2 of the second antenna unit 3, and the arrangement dimension D1 is set to a value larger than the arrangement dimension D2 of the second antenna unit 3. That means, they are set so that the first antenna unit 2 may be positioned outside and the second antenna unit 3 may be positioned inside. COPYRIGHT: (C)2004,JPO&NCIPI
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