| 摘要 |
PROBLEM TO BE SOLVED: To improve the performance of an antenna device. SOLUTION: When a detecting part 231 determines that a portable telephone set is opened, aλ/4 element 224 is set to be a second antenna element. At that time, a diversity antenna device is composed of a deformed monopole antenna element 223 being a first antenna element and theλ/4 element 224 being the second antenna element. A determining part 235 connects the deformed monopole antenna element 223 or theλ/4 element 224 to a radio circuit 232 in accordance with a communication state. When the portable telephone set is determined to be folded up, the deformed monopole antenna element 223 is operated by a high frequency signal from the radio circuit 232, and theλ/4 element 224 is grounded to be a passive element and is operated by electromagnetic coupling with the deformed monopole antenna element 223. The present invention is applicable to a portable telephone set. COPYRIGHT: (C)2004,JPO
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