| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an antenna device applicable to a system using a plurality of frequency bands. <P>SOLUTION: The antenna device is miniaturized by forming a linear radiation element by folding it, and the length of the linear radiation element is changed by providing a switch element in the middle of the linear radiation element to be adapted to a plurality of resonant frequencies. One part of the linear radiation element is caused to function as a parasitic radiation element, and the length is set at a length in which the device operates as a 1/4 wavelength monopole antenna having an operation frequency different from the operation frequency of the parasitic radiation element in a state that at least one part of the linear radiation element is connected to an electric feeding point. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
