| 摘要 |
An antenna system including an antenna device and feed device for transmitting and receiving circularly polarized RF waves in a first mode of operation, and of linearly polarized RF waves in a second mode of operation, and a hand-held mobile communication device provided with such an antenna system. A radiating structure (10) including N helical radiating elements (12A-D), being coextending and coaxially arranged on a support structure (11) are fed in order to provide for transmission/reception of circularly polarized RF waves in the first mode of operation. N is an integer greater than one. Further, means (24A-D, 16, 17, 19, 25, 25A) are arranged for essentially uniform excitation of the helical radiating elements (12A-D) in order to provide for transmission/reception of linearly polarized RF waves in the second mode of operation. |
