| 摘要 |
PROBLEM TO BE SOLVED: To suppress heat generation owing to the power loss of a radiating electrode and to reduce wavelength fluctuation by providing the radiating electrode whose one end is a free end in side an insulator and/or its outer face and providing an electrode whose width is larger than the line width of the radiating electrode at the other end of the radiating electrode. SOLUTION: An antenna has an electrode 3 whose width is larger than the line width of a radiating electrode 2 so that it is electrically connected to spiral radiating electrodes 2 formed on the outer face of an insulator 1. The electrode 3 is formed so that a ratio (b/a) between the line width (a) of a conductor line and the width (b) of the electrode 3 becomes 1.5-20. Heat generation owing to the power loss of the radiating electrode is radiated at the electrode 3, the temperature rises of the radiating electrodes 2 and the insulator 1 are suppressed and the fluctuation of an antenna wavelength can be reduced. When the ratio (b/a) between the maximum width (b) and the width (a) of the radiating electrodes 2 is below 1.5, it is not sufficient for radiating generated heat owing to the power loss of the radiating electrodes 2 at the electrode 3. When it exceeds 20, the insulator 1 should be enlarged.
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