| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a portable wireless device for maintaining a desired matching state even if impedance characteristics of an antenna are changed due to extension or housing of the antenna or casing deformation, and preventing an increase in the loss due to matching. Ž<P>SOLUTION: In the portable wireless device, two signal paths selectable by switching means 11, 15 are provided between an antenna 10 and a receiving circuit 16; a first low noise amplifier 13 amplifying a received high-frequency signal is provided in one of the paths; and a second low noise amplifier 18 having impedance characteristics different from those of the first low noise amplifier 13 is provided in the other signal path. A shape detection unit 20 detects the shape of the antenna 10 or the shape of the casing, and a control unit 21 automatically switches the two signal paths to use the two kinds of impedance matching states. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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