Multiband antenna
First Claim
1. An antenna structure comprising a helix element with varying distances between conductor turns, and a joining piece to which the helix element is attached by its one end galvanically, said joining piece being electrically conductive and unshielded to function as a radiator, and having fundamental resonance frequency lower than the seventh harmonic resonance frequency of said helix element.
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Accused Products
Abstract
The invention relates to a multiband antenna structure suitable for mobile stations in particular. The radiating elements of the antenna include not only a helix (210) but also the joining piece (220) that attaches the helix to the apparatus. The helix is shaped such that the distance between its conductor turns varies. The electrical length of the joining piece is increased e.g. by means of a conductive projection (226) that remains within the covering of the apparatus. By suitably dimensioning the parts, at least five of the resonances that the helix and joining piece have together and separately are arranged at useful points on the frequency scale. The structure according to the invention is despite the several bands simple and relatively low in production costs.
60 Citations
8 Claims
- 1. An antenna structure comprising a helix element with varying distances between conductor turns, and a joining piece to which the helix element is attached by its one end galvanically, said joining piece being electrically conductive and unshielded to function as a radiator, and having fundamental resonance frequency lower than the seventh harmonic resonance frequency of said helix element.
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7. A radio apparatus comprising an antenna having a helix element with varying distance between conductor turns, and a joining piece to which the helix element is attached galvanically by its one end, said joining piece being electrically conductive and unshielded to function as a part of the radiating structure of the antenna, and having fundamental resonance frequency lower than the seventh harmonic resonance frequency of said helix element.
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8. An antenna structure comprising a helix element with varying distances between conductor turns, and a joining piece to which the helix element is attached by its one end galvanically, said joining piece being electrically conductive and unshielded and having fundamental resonance frequency lower than the seventh harmonic resonance frequency of said helix element;
- and said joining piece further comprising a conductive projection to reduce the physical length of the joining piece in resonance.
Specification