US5694136A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antenna with R-card ground plane
Assignee: Trimble Inc
•
Filing: 1996-03-13
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Granted: 1997-12-02
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Expires: 2016-03-13
Abstract
Abstract An antenna structure has a radiating element and a ground plane. The ground plane has a central region relatively closely spaced apart from the radiating element and a peripheral region extending away from the central region. At least the peripheral region of the ground plane has a sheet resistivity that increases as radial distance from the central region increases. Though physically small, the ground plane simulates an infinite ground plane, and the antenna structure reduces multipath signals caused by reflection from the earth.
Inventors
- 👤 Brian G. Westfall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:11
CPC Classifications
H; H01; H01Q; H01Q1/00; H01Q1/36; H01Q1/38; H01Q9/00; H01Q9/04; H01Q9/0407
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
88 words
An antenna structure comprising: a radiating element for receiving broadcast signals directly and, because of reflection of the signals, also indirectly with a time delay, and a ground plane for said radiating element having a central region relatively closely spaced apart from said radiating element and a peripheral region extending away from said central region, at least the peripheral region of said ground plane having a sheet resistivity that increases as radial distance from said central region increases; whereby the signals received indirectly because of reflection are attenuated.
Claim 2
Dependent Claim
88 words
An antenna structure comprising: a radiating element for receiving broadcast signals directly and, because of reflection of the signals, also indirectly with a time delay, and a ground plane for said radiating element having a central region relatively closely spaced apart from said radiating element and a peripheral region extending away from said central region, at least the peripheral region of said ground plane having a sheet resistivity that increases as radial distance from said central region increases; whereby the signals received indirectly because of reflection are attenuated.
Claim 3
Dependent Claim
19 words
An antenna structure according to claim 1 wherein said sheet resistivity is a continuous function of said radial distance.
Claim 4
Dependent Claim
19 words
An antenna structure according to claim 1 wherein said sheet resistivity is a nonlinear function of said radial distance.
Claim 5
Dependent Claim
15 words
An antenna structure according to claim 1 wherein said sheet resistivity varies in discrete steps.
Claim 6
Dependent Claim
15 words
An antenna structure according to claim 1 wherein said radiating element comprises a patch antenna.
Claim 7
Dependent Claim
19 words
An antenna structure according to claim 1 wherein said radiating element and said ground plane have the same shape.
Claim 8
Dependent Claim
18 words
An antenna structure according to claim 1 wherein said radiating element and said ground plane are both square.
Claim 9
Dependent Claim
18 words
An antenna structure according to claim 1 wherein said radiating element and said ground plane are both circular.
Claim 10
Dependent Claim
18 words
An antenna structure according to claim 1 wherein said radiating element and said ground plane are both octagonal.
Claim 11
Dependent Claim
18 words
An antenna structure according to claim 1 wherein said radiating element and said ground plane have dissimilar shapes.
Claim 12
Dependent Claim
19 words
An antenna structure according to claim 1 wherein said radiating element is circular and said ground plane is square.
Claim 13
Dependent Claim
19 words
An antenna structure according to claim 1 wherein said radiating element is square and said ground plane is circular.
Claim 14
Dependent Claim
19 words
An antenna structure according to claim 1 wherein said radiating element is circular and said ground plane is octagonal.
Claim 15
Dependent Claim
19 words
An antenna structure according to claim 1 wherein said radiating element is square and said ground plane is octagonal.
Claim 16
Dependent Claim
17 words
An antenna structure according to claim 1 wherein said radiating element is centered over said ground plane.
Claim 17
Dependent Claim
13 words
An antenna structure according to claim 1 wherein said ground plane is planar.
Claim 18
Dependent Claim
16 words
An antenna structure according to claim 1 wherein said ground plane is frustoconical and concave up.
Claim 19
Dependent Claim
16 words
An antenna structure according to claim 1 wherein said ground plane is frustoconical and concave down.
Claim 20
Dependent Claim
16 words
An antenna structure according to claim 1 wherein said ground plane is frustopyramidal and concave up.
Claim 21
Dependent Claim
16 words
An antenna structure according to claim 1 wherein said ground plane is frustopyramidal and concave down.
Claim 22
Dependent Claim
19 words
An antenna structure according to claim 1 wherein said ground plane comprises a conductive disk in said central region.
Claim 23
Dependent Claim
17 words
An antenna structure according to claim 21 wherein said conductive disk is at least in part metallic.
Claim 24
Dependent Claim
19 words
An antenna structure according to claim 21 wherein said conductive disk is formed at least in part of aluminum.
Claim 25
Dependent Claim
56 words
An antenna structure according to claim 1 wherein said ground plane has a sheet resistivity approaching 3 ohms per square measured from dead center to a position adjacent the periphery of said radiating element and a sheet resistivity much higher than that of free space measured from dead center to the periphery of said ground plane.
Claim 26
Dependent Claim
35 words
An antenna structure according to claim 1 wherein the sheet resistivity in said peripheral region exceeds that in said central region by several orders of magnitude, whereby said ground plane simulates an infinite ground plane.
Claim 27
Dependent Claim
110 words
An antenna structure comprising: a radiating element and a ground plane for said radiating element having a central region relatively closely spaced apart from said radiating element and a peripheral region extending away from said central region, at least the peripheral region of said ground plane having a sheet resistivity that increases as radial distance from said central region increases, wherein at least the peripheral region of said ground plane comprises a nonconductive material and a material of varying sheet resistivity supported by said nonconductive material, said material of varying sheet resistivity having maximum thickness adjacent said central region and minimum thickness at the outer edge of said peripheral region.
Claim 28
Dependent Claim
110 words
An antenna structure comprising: a radiating element and a ground plane for said radiating element having a central region relatively closely spaced apart from said radiating element and a peripheral region extending away from said central region, at least the peripheral region of said ground plane having a sheet resistivity that increases as radial distance from said central region increases, wherein at least the peripheral region of said ground plane comprises a nonconductive material and a material of varying sheet resistivity supported by said nonconductive material, said material of varying sheet resistivity having maximum thickness adjacent said central region and minimum thickness at the outer edge of said peripheral region.
Claim 29
Dependent Claim
15 words
An antenna structure according to claim 26 wherein said nonconductive material comprises a woven cloth.
Claim 30
Dependent Claim
15 words
An antenna structure according to claim 26 wherein said nonconductive material comprises a plastic matrix.
Claim 31
Independent Claim
108 words
A method comprising the steps of: forming an antenna structure comprising: a radiating element for receiving broadcast signals directly and, because of reflection of the signals, also indirectly with a time delay, and a ground plane, wherein: the ground plane has a central region relatively closely spaced apart from the radiating element and a peripheral region extending away from the central region, and at least the peripheral region is formed of a material that has a sheet resistivity that increases as radial distance from the central region increases; and employing the antenna structure to receive the broadcast signals; whereby the signals received indirectly because of reflection are attenuated.
Claim 32
Independent Claim
108 words
A method comprising the steps of: forming an antenna structure comprising: a radiating element for receiving broadcast signals directly and, because of reflection of the signals, also indirectly with a time delay, and a ground plane, wherein: the ground plane has a central region relatively closely spaced apart from the radiating element and a peripheral region extending away from the central region, and at least the peripheral region is formed of a material that has a sheet resistivity that increases as radial distance from the central region increases; and employing the antenna structure to receive the broadcast signals; whereby the signals received indirectly because of reflection are attenuated.
Claim 33
Dependent Claim
14 words
A method according to claim 29 wherein the signals are broadcast by navigation satellites.
Claim 34
Dependent Claim
12 words
A method according to claim 30 wherein the signals are GPS signals.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-01 | 2001-06-02 | 2001-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-01 | 2005-06-02 | 2005-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-01 | 2009-06-02 | 2009-12-02 | $7700.00 | Window Closed / Lapsed |