| 摘要 |
PROBLEM TO BE SOLVED: To provide a sector antenna, where when one of a plurality of directional antennas on a plane is driven, it does not couple with others and its radiation characteristics are immune from adverse influences. SOLUTION: The sector antenna 100 has a plurality of directional antennas, arranged at approximately equal intervals along a virtual circle and being flush with each other. The directional antennas 10, 20,..., 50 are arranged so that their respective beam directions D1, D2,..., D5 coincide with the null directions of the radiation patterns of adjacent directional antennas in the beam directions. This results in a very weak coupling with adjacent other directional antennas to exist in the beam direction of the directional antenna. Hence adverse influences due to coupling with others on each directional antenna are very small and thus will not degrade the radiation characteristics. Thus even if the directional antennas are disposed close to each other, the radiation characteristics will not deteriorate and miniaturization is also facilitated.
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