| 摘要 |
The invention relates to double-action antenna structures. The structure comprises e.g. a PIFA-type antenna inside the casing of a mobile station, a coupling element and a whip element movable in relation to the former two. The coupling element (240) is a relatively small conductive element between the radiating plane (220) and ground plane (210) of the PIFA, galvanically isolated from the radiating plane and ground plane. When the whip element (230) is retracted, it has no significant coupling to the PIFA parts. When the whip element is extended, its lower end (231) is galvanically connected to the coupling element so that a significant electromagnetic coupling is established between the whip element and the radiating plane of the PIFA. Thus the whip element is fed through the PIFA without being in galvanic contact with it. The coupling element further provides for the matching of the whip element. In the structure according to the invention the internal and external antennas may be designed and optimized relatively independently of each other. The structure is also relatively simple because no mechanical parts or components are needed for the matching.
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