Broad band antenna structure
First Claim
1. An antenna structure, comprising:
- a first antenna arm for receiving radio frequency waves, said first antenna arm having a first spiral shape and being defined by a first antenna element disposed in a first zig-zag configuration that has a logarithmic periodic characteristic and extends outwardly from a lateral center axis, said logarithmic periodic characteristic contributing to the determination of a first bandwidth of said first antenna arm, wherein said first antenna arm receives said radio frequency waves about a first longitudinal center axis of said first antenna arm and said first zig-zag antenna element configuration; and
feed means for conducting radio frequency signals from said first antenna element.
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Accused Products
Abstract
An antenna structure is provided having one or more spiral antenna arms extending outwardly from a lateral center axis. Each arm is defined by an antenna element disposed in a zig-zag configuration to provide reactive loading to the arm, wherein each arm receives or transmits radio frequency waves about a longitudinal center axis of the arm and the zig-zag element configuration. Thus, the antenna structure has a broader bandwidth than other antennas requiring the same amount of space. The antenna structure also has a substantially omni-directional radiation pattern and a low profile. Each antenna element can be metallisation disposed on a support structure or can be one or more cable conductors. A feed means is provided which can be connected to the elements proximate to the lateral center axis and positioned along or coincident with the longitudinal center axis of one arm or can be connected to one of the elements distal to the lateral center axis. In both methods of feeding the antenna arms, the antenna elements function as part of an infinite balun. In one application, the antenna structure is secured within the non-metallic roof structure of an automobile.
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Citations
46 Claims
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1. An antenna structure, comprising:
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a first antenna arm for receiving radio frequency waves, said first antenna arm having a first spiral shape and being defined by a first antenna element disposed in a first zig-zag configuration that has a logarithmic periodic characteristic and extends outwardly from a lateral center axis, said logarithmic periodic characteristic contributing to the determination of a first bandwidth of said first antenna arm, wherein said first antenna arm receives said radio frequency waves about a first longitudinal center axis of said first antenna arm and said first zig-zag antenna element configuration; and feed means for conducting radio frequency signals from said first antenna element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An antenna structure, comprising:
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a first antenna arm for receiving radio frequency waves, said first antenna arm having a first spiral shape and being defined by a first antenna element disposed in a first zig-zag configuration extending outwardly from a lateral center axis to provide reactive loading to said first antenna arm, wherein said first antenna arm receives said radio frequency waves about a first longitudinal center axis of said first antenna arm and said first zig-zag antenna element configuration; and feed means for conducting radio frequency signals from said first antenna element; a second antenna arm for receiving radio frequency waves, said second antenna arm having a second spiral shape and being defined by a second antenna element disposed in a second zig-zag configuration extending outwardly from said lateral center axis of said first antenna arm to provide reactive loading to said second antenna arm, wherein said second antenna arm receives said radio frequency waves about a second longitudinal center axis of said second antenna arm and said second zig-zag antenna element configuration; said first and second antenna arms are disposed substantially uniformly about said lateral center axis; said first antenna element has a first proximate end located proximate to said lateral central axis and a first distal end located distal to said lateral central axis; said second antenna element has a second proximate end located proximate to said lateral central axis and a second distal end located distal to said lateral central axis; said feed means includes a feed coaxial cable having a feed inner conductor and a feed outer conductor that is electrically insulated from said feed inner conductor; said first antenna element comprises a first coaxial cable having a first inner conductor and a first outer conductor that is electrically insulated from said first inner conductor, said first inner conductor and said first outer conductor each include said first proximate end and said first distal end; said second antenna element comprises a second coaxial cable having a second inner conductor and a second outer conductor that is electrically insulated from said second inner conductor, said second inner conductor and said second outer conductor each include said second proximate end and said second distal end; said feed outer conductor of said feed coaxial cable is electrically connected to said first distal end of said first outer conductor of said first coaxial cable; said feed inner conductor of said feed coaxial cable is electrically connected to said first distal end of said first inner conductor of said first coaxial cable; and said first proximate end of said first inner conductor of said first coaxial cable is electrically connected to said second proximate end of said second outer conductor of said second coaxial cable.
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17. An antenna structure, comprising:
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a first antenna arm for receiving radio frequency waves, said first antenna arm having a first spiral shape and being defined by a first antenna element disposed in a first logarithmic periodic zig-zag configuration extending outwardly from a lateral center axis, said first logarithmic period zig-zag configuration contributing to the determination of a first bandwidth of said first antenna arm, wherein said first antenna arm receives said radio frequency waves about a first longitudinal center axis of said first antenna arm and said first logarithmic periodic zig-zag antenna element configuration; a second antenna arm for receiving radio frequency waves, said second antenna arm having a second spiral shape and being defined by a second antenna element disposed in a second zig-zag configuration extending outwardly from said lateral center axis of said first antenna arm to provide reactive loading to said second antenna arm, wherein said second antenna arm receives said radio frequency waves about a second longitudinal center axis of said second antenna arm and said second zig-zag antenna element configuration, said first and second antenna arms disposed substantially uniformly about said lateral center axis; and feed means for conducting radio frequency signals from said first and second antenna elements, said feed means including an infinite balun. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. An antenna structure, comprising:
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a first antenna arm for receiving radio frequency waves, said first antenna arm having a first spiral shape and being defined by a first antenna element disposed in a first zig-zag configuration extending outwardly from a lateral center axis to provide reactive loading to said first antenna arm, wherein said first antenna arm receives said radio frequency waves about a first longitudinal center axis of said first antenna arm and said first zig-zag antenna element configuration; a second antenna arm for receiving radio frequency waves, said second antenna arm having a second spiral shape and being defined by a second antenna element disposed in a second zig-zag configuration extending outwardly from said lateral center axis of said first antenna arm to provide reactive loading to said second antenna arm, Wherein said second antenna arm receives said radio frequency waves about a second longitudinal center axis of said second antenna arm and said second zig-zag antenna element configuration, said first and second antenna arms disposed substantially uniformly about said lateral center axis; feed means for conducting radio frequency signals from said first and second antenna elements, said feed means including an infinite balun; said first antenna element comprises a first outer conductor of a first coaxial cable having a first proximate end located proximate to said lateral central axis and a second distal end located distal to said lateral central axis; said second antenna element comprises a second outer conductor of a second coaxial cable having a second proximate end located proximate to said lateral central axis and a second distal end located distal to said lateral central axis; said feed means includes a feed coaxial cable having a feed inner conductor and a feed outer conductor that is electrically insulated from said feed inner conductor; said feed outer conductor of said feed coaxial cable is electrically connected to said first distal end of said first outer conductor of said first coaxial cable; said feed inner conductor of said feed coaxial cable is electrically connected to said first distal end of a first inner conductor of said first coaxial cable; and said first proximate end of said first inner conductor of said first coaxial cable is electrically connected to said second proximate end of said second outer conductor of said second coaxial cable. - View Dependent Claims (28)
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29. An antenna structure comprising:
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a first antenna arm for receiving radio frequency waves, said first antenna arm having a first spiral shape and being defined by a first antenna element disposed in a first zig-zag configuration extending outwardly from a lateral center axis to provide reactive loading to said first antenna arm, wherein said first antenna arm receives said radio frequency waves about a first longitudinal center axis of said first antenna arm and said first zig-zag antenna element configuration; a second antenna arm for receiving radio frequency waves, said second antenna arm having a second spiral shape and being defined by a second antenna element disposed in a second zig-zag configuration extending outwardly from said lateral center axis of said first antenna arm to provide reactive loading to said second antenna arm, wherein said second antenna arm receives said radio frequency waves about a second longitudinal center axis of said second antenna arm and said second zig-zag antenna element configuration, said first and second antenna arms disposed substantially uniformly about said lateral center axis; feed means for conducting radio frequency signals from said first and second antenna elements, said feed means including an infinite balun; said first antenna element comprises a first outer conductor of a first coaxial cable having a first proximate end located proximate to said lateral central axis and a second distal end located distal to said lateral central axis; said second antenna element comprises a second outer conductor of a second coaxial cable having a second proximate end located proximate to said lateral central axis and a second distal end located distal to said lateral central axis; said feed means includes a feed coaxial cable having a feed inner conductor and a feed outer conductor that is electrically insulated from said feed inner conductor; one of said feed inner conductor and said feed outer conductor of said feed coaxial cable is electrically connected to one of said first proximate end of said first outer conductor of said first coaxial cable and said second proximate end of said second outer conductor of said second coaxial cable; and the other of said feed inner conductor and said feed outer conductor of said feed coaxial cable is electrically connected to the other of said first proximate end of said first outer conductor of said first coaxial cable and said second proximate end of said second outer conductor of said second coaxial cable. - View Dependent Claims (30, 31)
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32. An antenna structure for use in conjunction with a mobile receiver, the antenna structure comprising:
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an insulating support member; a first antenna arm for receiving radio frequency waves, said first antenna arm having a first equiangular spiral shape and being defined by a first antenna element comprising a first single conductor disposed on said support member in a first logarithmic periodic zig-zag configuration extending outwardly from a lateral center axis, said first logarithmic periodic zig-zag configuration contributing to the determination of a first bandwidth of said first antenna arm, wherein said first antenna arm receives said radio frequency waves about a first longitudinal center axis of said first antenna arm and said first logarithmic periodic zig-zag antenna element configuration; a second antenna arm for receiving radio frequency waves, said second antenna arm having a second equiangular spiral shape and being defined by a second antenna element comprising a second single conductor disposed on said support member in a second logarithmic periodic zig-zag configuration extending outwardly from said lateral center axis of said first antenna arm, said second logarithmic periodic zig-zag configuration contributing to a determination of a second bandwidth of said second antenna arm, wherein said second antenna arm receives said radio frequency waves about a second longitudinal center axis of said second antenna arm and said second logarithmic periodic zig-zag antenna element configuration, said first and second antenna arms disposed substantially uniformly about said lateral center axis; and feed means for conducting radio frequency signals from said first and second antenna elements, said feed means including an infinite balun. - View Dependent Claims (33, 34, 35)
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36. An antenna structure, comprising:
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an antenna for transmitting/receiving radio frequency signals, said antenna including a first antenna arm that extends outwardly from a lateral center axis and includes a first logarithmic periodic element which extends laterally from a first longitudinal center axis of said first antenna arm to define a first spiral shape; and feed means for conducting radio frequency signals between said antenna and other circuitry; wherein said logarithmic periodic element has a zig-zag configuration. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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Specification