| 摘要 |
When three or more antennas and a plurality of wireless circuits using wireless frequency bands near to each other are installed on a cabinet whose size is limited, degradation of characteristic caused by electromagnetic coupling between antennas is suppressed. When a first antenna 21 and a second antenna 22 are connected to a first wireless circuit 31, a third antenna 23 is connected to a second wireless circuit 32, and an operation frequency band of the second wireless circuit 32 is near in a higher band than an operation frequency band of the first wireless circuit 31, a feeding point 23a of the third antenna is placed at a position nearer to a feeding point 21a of the first antenna than the feeding point 22a of the second antenna. In the operation frequency band of the first wireless circuit 31, the gain of the first antenna 21 is set higher than the gain of the second antenna 22 in a low frequency band and the gain of the first antenna 21 is set higher than the gain of the second antenna 22 in a high frequency band.
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