| 摘要 |
PROBLEM TO BE SOLVED: To provide an antenna system that can be miniaturized and from which a desired radiation pattern can easily be obtained. SOLUTION: This antenna system is provided with a linear element 102 connected to one end of a case 101, and linear elements 103, 104 connected to one end of the linear element 102. A feeding point 105 is provided between the casing and the linear element 102. The linear elements 103, 104 are arranged in directions different by about 180 degrees at the boundary of a connecting point between the linear element 102 and the linear elements 103, 104. The sum of the lengths of the linear elements 103, 104 is selected to be an integer multiple of a half of the wavelength with respect to a radiation frequency of a radio wave and the electric length of the linear element 102 is selected to be a half or below the absolute value of the difference of the electric length between the linear elements 103 and 104. Thus, the antenna system can suppress undesired frequency components and emit a radio wave with a desired frequency. Furthermore, the antenna system can prevent spurious radiation from its feeder and can be miniaturized. Moreover, the antenna system provides a radiation pattern close to the omnidirectional pattern.
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