Dual-band helix antenna with parasitic element and associated methods of operation
First Claim
1. An antenna system for transmitting and receiving electrical signals in two widely separated frequency bands, comprising:
- a helix antenna having a single helix element; and
a parasitic element positioned diagonally through the interior of said helix element;
wherein said parasitic element is positioned so that when radio frequency energy in the higher of said frequency bands is incident on said antenna system, said helix element and said parasitic element are capacitively coupled, while when radio frequency energy in the lower of said frequency bands is incident on said antenna system, said helix element is substantially isolated from said parasitic element.
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Accused Products
Abstract
Antenna systems for transmitting and receiving electrical signals in two widely separated frequency bands are provided which comprise a helix antenna and a parasitic element which is adjacent to the helix antenna. The parasitic element is positioned so that when radio frequency energy in the higher of the frequency bands is incident on the antenna system, the helix antenna and the parasitic element are capacitively coupled, while when radio frequency energy in the lower of the frequency bands is incident on the antenna system, the helix antenna is substantially isolated from the parasitic element. The effective aperture of the antenna system is preferably substantially the same in both of the frequency bands of operation, and the parasitic element may be positioned either inside or outside of the helix antenna, and may be parallel to the major-axis of the helix, or alternatively, may be positioned diagonally so as to only be adjacent to two or more windings of the helix antenna. Additionally, the antenna system may be implemented in combination with a radiotelephone having a transmitter, a receiver, a user interface, and an antenna feed system.
67 Citations
25 Claims
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1. An antenna system for transmitting and receiving electrical signals in two widely separated frequency bands, comprising:
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a helix antenna having a single helix element; and a parasitic element positioned diagonally through the interior of said helix element; wherein said parasitic element is positioned so that when radio frequency energy in the higher of said frequency bands is incident on said antenna system, said helix element and said parasitic element are capacitively coupled, while when radio frequency energy in the lower of said frequency bands is incident on said antenna system, said helix element is substantially isolated from said parasitic element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A dual-band antenna system for transmitting and receiving electrical signals in the 824 to 894 MHz and the 1850 to 1990 MHz frequency bands, comprising:
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a helix antenna having a single helix element designed to resonate in the 824 to 894 MHz frequency band; and a parasitic element adjacent to said helix element which is sized and positioned so that when said antenna system operates in the 1850 to 1990 MHz frequency band, radio frequency energy incident on said helix element is capacitively coupled to and from said parasitic element, while when said antenna system operates in the 824 to 894 MHz frequency band, radio frequency energy incident on said helix element is substantially isolated from said parasitic element. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method of making an antenna system for communicating in two separate frequency bands, the method comprising the steps of:
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providing a helix antenna having a single helix element; providing a parasitic element adjacent to the helix element; sizing and positioning the parasitic element so that when radio frequency energy in the higher of the frequency bands is incident on the antenna system, the helix element and the parasitic element are capacitively coupled, while when radio frequency energy in the lower of the frequency bands is incident on the antenna system, the helix element is substantially isolated from the parasitic element and so that the effective aperture of the antenna system is substantially the same in both of the frequency bands. - View Dependent Claims (20, 21)
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22. A method of receiving signals using a dual-band antenna system comprising a helix antenna having a single helix element and a parasitic element positioned adjacent the helix element, the method comprising the steps of:
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receiving signals via the helix element in a first frequency band that corresponds to the resonant frequency of the helix element while substantially isolating the parasitic element from the helix element; and receiving signals via the combination of the helix element and the parasitic element in a second frequency band which is higher than the first frequency band. - View Dependent Claims (23, 24)
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25. A method of making an antenna system for communicating in two separate frequency bands, the method comprising the steps of:
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providing a helix antenna having a single helix element; providing a parasitic element adjacent to the helix element; positioning the parasitic element diagonally through the interior of the helix element so that when radio frequency energy in the higher of the frequency bands is incident on the antenna system, the helix element and the parasitic element are capacitively coupled, while when radio frequency energy in the lower of the frequency bands is incident on the antenna system, the helix element is substantially isolated from the parasitic element and so that the effective aperture of the antenna system is substantially the same in both of the frequency bands.
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Specification