| 摘要 |
An antenna for small mobile devices comprises an antenna rod retractable in an antenna cover, the rod having an extended position, when the device operates in an active mode, or a retracted position, when the device operates in a passive mode. The electrical length of the antenna is different in the respective modes. Further, the antenna rod comprises an upper section and a lower section, separated from each other by an intermediate electrically insulating portion, wherein the upper section forms an antenna in a passive mode and the two sections in the active mode. |
