| 摘要 |
The invention relates to a multiband antenna which finds utility particularly in mobile stations. The antenna structure includes a PIFA-type antenna positioned inside the covers of a mobile station, which antenna includes a slot radiator (231). In the planar element there is a second slot (232) so that, viewed from a feed point (F), two radiating conductive branches (B1, B2) of different lengths are formed. Each of the three radiators has a separate operating band of its own. The structure also includes a whip element (211) movable with respect to the PIFA part. When the whip element is pulled out, its lower end is galvanically coupled with the shorter branch of the planar element, with its relatively narrow side branch (B12). The whip enhances the operation of the antenna especially in the lowest operating band. The influence of the pulled-out whip on the location of the uppermost operating band is compensated for by a third slot (233) in the planar element. Matching for the whip element is provided by shaping the conductive patterns existing in the planar element in any case. The structure is relatively simple and economical to fabricate. A good three-band planar antenna can be provided without a whip element as well. <IMAGE> |
