| 摘要 |
PCT No. PCT/GB96/02373 Sec. 371 Date Mar. 27, 1998 Sec. 102(e) Date Mar. 27, 1998 PCT Filed Sep. 26, 1996 PCT Pub. No. WO97/12417 PCT Pub. Date Apr. 3, 1997An antenna (1) comprises a first elongate antenna element (3) for connection, in use, to a signal carrying element of an apparatus with which the antenna is used, and a shorter second antenna element (5) extending substantially around a proximal end portion (9) of the first antenna element (3), a proximal end (6) of the second element (5) being connected to the proximal end (8) of the first element. A body (12) of a dielectric material is disposed between the first and second antenna elements (3,5). The antenna (1) has at least two optimum operating frequencies, each with an associated usable bandwidth, which bandwidths preferably overlap. The antenna (1) may include further antenna elements (20,22) which further extend the overall usable bandwidth (Bu) of the antenna (1). One or more "ground plane" elements (16,17) are preferably also provided in the antenna for decoupling the first and second antenna elements (3,5) from an earthed screen or element in the apparatus with which the antenna is used. |
