| 摘要 |
The antenna (9) is mounted on the housing of a hand- portable device e.g a mobile telephone, an includes a feed section (7) and an antenna whip (8) arranged to slide into and out of the telephone to retracted and extended positions, in combination with a multi-band helical structure (1,2). Two helical radiating elements (1,2) are mounted in helical grooves (3,4) of a dielectric carrier (5) which includes a cylindrical opening extending longitudinally through the centre of the carrier. The two helices (1,2) have approximately the same axial length, with the inner coil (1) having a smaller diameter and greater pitch than the outer coil (2). This enables the structure to resonate at different frequencies in widely separated frequency bands. The antenna whip (8) includes straight radiator in a lower portion, and an upper portion which is non- conductive and provided with a knob. |
