| 摘要 |
PROBLEM TO BE SOLVED: To easily provide a desired radiation pattern by fitting a half-wave dipole antenna close to the surface of a metallic casing incorporating a radio machine, connecting the antenna and the radio machine by means of a feeder and connecting the feeder and the metallic casing by means of a reactance element. SOLUTION: A dipole antenna 101 is arranged so that it becomes parallel to one side of a casing 102. The casing is a conductor and is the shield of a radio circuit. A feeder 103 is arranged close to the surface of the casing 102 from the feeding point of the dipole antenna 101. A reactance element is arranged between the feeder 103 and the casing 102 by connecting them. The reactance element is constituted of a capacitor, an inductance and a variable capacitor. The antenna device returns a radiation pattern changed by the feeder 103 to the original one and is made into the desired radiation pattern.
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