US5986615A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antenna with ground plane having cutouts
Assignee: Trimble Inc
•
Filing: 1997-09-19
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Granted: 1999-11-16
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Expires: 2017-09-19
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. The peripheral region comprises at least the conductive layer that extends radially beyond the radiating element and provides a sheet resistivity higher than that of the radiating element. 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
- 👤 Kevin B. Stephenson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:01
CPC Classifications
H; H01; H01Q; H01Q1/00; H01Q1/48
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
80 words
An antenna structure comprising: a radiating element and a ground plane for the radiating element having a central region closely spaced apart from the radiating element and a peripheral region extending away from the central region, wherein: the peripheral region is formed with at least one cutout having an area that increases as radial distance from said central region increases to provide an equivalent sheet resistivity of the ground plane that increases as radial distance from said central region increases.
Claim 2
Dependent Claim
80 words
An antenna structure comprising: a radiating element and a ground plane for the radiating element having a central region closely spaced apart from the radiating element and a peripheral region extending away from the central region, wherein: the peripheral region is formed with at least one cutout having an area that increases as radial distance from said central region increases to provide an equivalent sheet resistivity of the ground plane that increases as radial distance from said central region increases.
Claim 3
Dependent Claim
43 words
An antenna structure according to claim 1 wherein the peripheral region is formed with a plurality of cutouts, each cutout being substantially U- or V-shaped and having a narrow end near said central region and a wide end remote from said central region.
Claim 4
Dependent Claim
44 words
An antenna structure according to claim 1 wherein the peripheral region is formed with a plurality of radial cutouts, each cutout being substantially U- or V-shaped and having a narrow end near said central region and a wide end remote from said central region.
Claim 5
Dependent Claim
13 words
An antenna structure according to claim 1 wherein said cutout describes a spiral.
Claim 6
Dependent Claim
33 words
An antenna structure according to claim 1 wherein said cutout describes a spiral about a central point, said spiral subtending an arc of at least 360 degrees as measured from said central point.
Claim 7
Dependent Claim
34 words
An antenna structure according to claim 1 wherein said cutout describes a spiral about a central point, said spiral subtending an arc of a multiple of 360 degrees as measured from said central point.
Claim 8
Dependent Claim
52 words
An antenna structure according to claim 1 wherein said cutout describes a spiral about a central point, said spiral subtending an arc of a multiple of 360 degrees as measured from said central point and forming loops that are closer together or become wider as radial distance from said central region increases.
Claim 9
Dependent Claim
23 words
An antenna structure according to claim 1 wherein the peripheral region is formed with a plurality of cutouts, each cutout describing a spiral.
Claim 10
Dependent Claim
41 words
An antenna structure according to claim 1 wherein the peripheral region is formed with a plurality of cutouts, each cutout being a closed figure and the cutouts collectively having an area that increases as radial distance from said central region increases.
Claim 11
Dependent Claim
39 words
An antenna structure according to claim 1 wherein the peripheral region is formed with a plurality of cutouts, each cutout being elliptical and the cutouts collectively having an area that increases as radial distance from said central region increases.
Claim 12
Dependent Claim
39 words
An antenna structure according to claim 1 wherein the peripheral region is formed with a plurality of cutouts, each cutout being circular and the cutouts collectively having an area that increases as radial distance from said central region increases.
Claim 13
Dependent Claim
39 words
An antenna structure according to claim 1 wherein the peripheral region is formed with a plurality of cutouts, each cutout being polygonal and the cutouts collectively having an area that increases as radial distance from said central region increases.
Claim 14
Dependent Claim
39 words
An antenna structure according to claim 1 wherein the peripheral region is formed with a plurality of cutouts, each cutout being rectangular and the cutouts collectively having an area that increases as radial distance from said central region increases.
Claim 15
Dependent Claim
39 words
An antenna structure according to claim 1 wherein the peripheral region is formed with a plurality of cutouts, each cutout being square and the cutouts collectively having an area that increases as radial distance from said central region increases.
Claim 16
Dependent Claim
60 words
An antenna structure according to claim 1 wherein the peripheral region has a periphery and is formed with a first plurality of cutouts each extending from the central region to the periphery and a second plurality of cutouts interspersed with the first plurality of cutouts and each extending from a position spaced apart from the central region to the periphery.
Claim 17
Dependent Claim
62 words
An antenna structure according to claim 1 wherein the peripheral region has a periphery and is formed with a first plurality of radial cutouts each extending from the central region to the periphery and a second plurality of radial cutouts interspersed with the first plurality of cutouts and each extending from a position spaced apart from the central region to the periphery.
Claim 18
Dependent Claim
15 words
An antenna structure according to claim 1 wherein the radiating element comprises a patch antenna.
Claim 19
Dependent Claim
19 words
An antenna structure according to claim 1 wherein the radiating element and the ground plane have the same shape.
Claim 20
Dependent Claim
18 words
An antenna structure according to claim 1 wherein the radiating element and the ground plane are both square.
Claim 21
Dependent Claim
18 words
An antenna structure according to claim 1 wherein the radiating element and the ground plane are both circular.
Claim 22
Dependent Claim
18 words
An antenna structure according to claim 1 wherein the radiating element and the ground plane are both octagonal.
Claim 23
Dependent Claim
18 words
An antenna structure according to claim 1 wherein the radiating element and the ground plane have dissimilar shapes.
Claim 24
Dependent Claim
19 words
An antenna structure according to claim 1 wherein the radiating element is circular and the ground plane is square.
Claim 25
Dependent Claim
19 words
An antenna structure according to claim 1 wherein the radiating element is square and the ground plane is circular.
Claim 26
Dependent Claim
19 words
An antenna structure according to claim 1 wherein the radiating element is circular and the ground plane is octagonal.
Claim 27
Dependent Claim
19 words
An antenna structure according to claim 1 wherein the radiating element is square and the ground plane is octagonal.
Claim 28
Dependent Claim
17 words
An antenna structure according to claim 1 wherein the radiating element is centered over the ground plane.
Claim 29
Dependent Claim
13 words
An antenna structure according to claim 1 wherein the ground plane is planar.
Claim 30
Dependent Claim
16 words
An antenna structure according to claim 1 wherein the ground plane is frustoconical and concave up.
Claim 31
Dependent Claim
16 words
An antenna structure according to claim 1 wherein the ground plane is frustoconical and concave down.
Claim 32
Dependent Claim
19 words
An antenna structure according to claim 1 wherein the ground plane comprises a conductive disk in the central region.
Claim 33
Dependent Claim
26 words
An antenna structure according to claim 1 wherein the ground plane comprises a conductive disk in the central region that is at least in part metallic.
Claim 34
Dependent Claim
28 words
An antenna structure according to claim 1 wherein the ground plane comprises a conductive disk in the central region that is at least in part formed of aluminum.
Claim 35
Dependent Claim
53 words
An antenna structure according to claim 1 wherein the ground plane has a sheet resistivity approaching 3 ohms per square measured from dead center to the periphery of the radiating element and a sheet resistivity much higher than that of free space measured from dead center to the periphery of the ground plane.
Claim 36
Dependent Claim
35 words
An antenna structure according to claim 1 wherein the sheet resistivity in the peripheral region exceeds that in the central region by several orders of magnitude, whereby the ground plane simulates an infinite ground plane.
Claim 37
Independent Claim
125 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 closely spaced apart from the radiating element and a peripheral region extending away from the central region, and the peripheral region is formed with at least one cutout having an area that increases as radial distance from said central region increases to provide an equivalent sheet resistivity of the ground plane that increases as radial distance from said central region increases; and employing the antenna structure to receive the broadcast signals; whereby the signals received indirectly because of reflection are attenuated.
Claim 38
Independent Claim
125 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 closely spaced apart from the radiating element and a peripheral region extending away from the central region, and the peripheral region is formed with at least one cutout having an area that increases as radial distance from said central region increases to provide an equivalent sheet resistivity of the ground plane that increases as radial distance from said central region increases; and employing the antenna structure to receive the broadcast signals; whereby the signals received indirectly because of reflection are attenuated.
Claim 39
Dependent Claim
14 words
A method according to claim 36 wherein the signals are broadcast by navigation satellites.
Claim 40
Dependent Claim
12 words
A method according to claim 36 wherein the signals are GPS signals.
References Cited (Backward Citations)
GB2057773A
Cited
US4529987A
Cited
DE3738513A1
Cited
US5061938A
Cited
EP0318873A1
Cited
US4927251A
Cited
EP0394960A1
Cited
US4965603A
Cited
US5132623A
Cited
US5248980A
Cited
US5170175A
Cited
US5204685A
Cited
DE4326117A1
Cited
US5592174A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-11-15 | 2003-05-17 | 2003-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-11-15 | 2007-05-17 | 2007-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-11-15 | 2011-05-17 | 2011-11-16 | $7700.00 | Window Closed / Lapsed |