Patent US5220335A successfully refreshed from Google Patents.
US5220335A
Expired / Lapsed
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Planar microstrip Yagi antenna array
Assignee: California Institute of Technology
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Filing: 1991-02-28
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Granted: 1993-06-15
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Expires: 2011-02-28
Abstract
Abstract A directional microstrip antenna includes a driven patch surrounded by an isolated reflector and one or more coplanar directors, all separated from a groundplane on the order of 0.1 wavelength or less to provide endfire beam directivity without requiring power dividers or phase shifters. The antenna may be driven at a feed point a distance from the center of the driven patch in accordance with conventional microstrip antenna design practices for H-plane coupled or horizontally polarized signals. The feed point for E-plane coupled or vertically polarized signals is at a greater distance from the center than the first distance. This feed point is also used for one of the feed signals for circularly polarized signals. The phase shift between signals applied to feed points for circularly polarized signals must be greater than the conventionally required 90° and depends upon the antenna configuration.
Inventors
- 👤 John Huang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:20
CPC Classifications
H; H01; H01Q; H01Q19/00; H01Q19/28; H01Q19/30; H01Q1/00; H01Q1/36; H01Q1/38; H01Q19/005
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
253 words
A directional microstrip array antenna comprising: a dielectric substrate having first and second surfaces; a group plane on the first surface of the substrate; a square driven patch on the second surface of the substrate connected to a source or receiver of power, the separation between said driven patch and said groundplane being 0.1 wavelength or less; a square isolated reflector patch coplanar with the driven patch on one side thereof for mutual coupling there between, the center to center distance between the driven and reflector patches being 0.35 free space wavelength; a square first isolated director patch coplanar with the driven patch on the side opposite said one side of said reflector patch, the center to center distance between the driven and director patches being 0.30 free wavelength; first feed point means for applying a first signal along a midline of the driven patch transverse to an antenna array axis at a first distance from the center of the driven patch; and second feed point means for applying a second signal along a midline of the driven patch parallel to the antenna array axis at a second distance from the center of the driven patch, said first and second distances being different and said second signal having a phase shift relative to said first signal in the range of 115° so that the antenna is circularly polarized, whereby the antenna beam is tilted toward the axis of the antenna array by the parasitic coupling across gaps between the driven and isolated patches.
Claim 2
Dependent Claim
253 words
A directional microstrip array antenna comprising: a dielectric substrate having first and second surfaces; a group plane on the first surface of the substrate; a square driven patch on the second surface of the substrate connected to a source or receiver of power, the separation between said driven patch and said groundplane being 0.1 wavelength or less; a square isolated reflector patch coplanar with the driven patch on one side thereof for mutual coupling there between, the center to center distance between the driven and reflector patches being 0.35 free space wavelength; a square first isolated director patch coplanar with the driven patch on the side opposite said one side of said reflector patch, the center to center distance between the driven and director patches being 0.30 free wavelength; first feed point means for applying a first signal along a midline of the driven patch transverse to an antenna array axis at a first distance from the center of the driven patch; and second feed point means for applying a second signal along a midline of the driven patch parallel to the antenna array axis at a second distance from the center of the driven patch, said first and second distances being different and said second signal having a phase shift relative to said first signal in the range of 115° so that the antenna is circularly polarized, whereby the antenna beam is tilted toward the axis of the antenna array by the parasitic coupling across gaps between the driven and isolated patches.
Claim 3
Dependent Claim
36 words
The directional microstrip antenna claimed in claim 1, wherein the second distance is greater than the first distance and selected so that the impedances of the driven patch at the points of signal application are equal.
Claim 4
Dependent Claim
30 words
The directional microstrip antenna claimed in claim 1, further comprising: means for producing the second signal by applying a phase shift in the range of 115° to the first signal.
Claim 5
Dependent Claim
94 words
The directional microstrip antenna claimed in claim 1 further comprising: a second director patch coplanar with the first director patch, wherein the first and second director patch each have a size and the first director patch is separated from the driven patch by a first gap dimension and the second director patch is separated from the first director patch by a second gap dimension and the size of the second director patch is equal to the size of the first director patch and the first gap dimension is equal to the second gap dimension.
Claim 6
Dependent Claim
30 words
The directional microstrip antenna claimed in claim 1 wherein: the ratio between the size of the reflector patch and the size of the driven patch is between 1.1:1 and 1.3:1.
Claim 7
Dependent Claim
30 words
The directional microstrip antenna claimed in claim 1 wherein: the ratio between the size of the driven patch and the size of the director patch is between 1:0.8 and 1:0.95.
Claim 8
Dependent Claim
25 words
The directional microstrip antenna claimed in claim 1 wherein: the relative dielectric constant of the dielectric substrate is in the range between 1.5 and 5.0.
Claim 9
Independent Claim
186 words
A method of tilting the beam of a microstrip array antenna toward an axis of the array, comprising the steps of: driving a square driven patch separated by a dielectric 0.1 free space wavelength or less from a groundplane; parasitically coupling a larger square reflector patch to the driven patch, the center to center distances between the patches being 0.35 free space wavelength; parasitically coupling a smaller square director patch to the driven patch on the side opposite the reflector patch, the center to center distances between the driven and director patches being 0.30 free space wavelength; applying a first signal along a midline of the driven patch transverse to the antenna array axis at a first distance from the center of the driven patch; and applying a second signal along a midline of the driven patch parallel to the antenna array axis at a second distance from the center of the driven patch, said first and second distances being different and said second signal having a phase shift relative to said first signal in the range of 115° so that the antenna is circularly polarized.
Claim 10
Independent Claim
186 words
A method of tilting the beam of a microstrip array antenna toward an axis of the array, comprising the steps of: driving a square driven patch separated by a dielectric 0.1 free space wavelength or less from a groundplane; parasitically coupling a larger square reflector patch to the driven patch, the center to center distances between the patches being 0.35 free space wavelength; parasitically coupling a smaller square director patch to the driven patch on the side opposite the reflector patch, the center to center distances between the driven and director patches being 0.30 free space wavelength; applying a first signal along a midline of the driven patch transverse to the antenna array axis at a first distance from the center of the driven patch; and applying a second signal along a midline of the driven patch parallel to the antenna array axis at a second distance from the center of the driven patch, said first and second distances being different and said second signal having a phase shift relative to said first signal in the range of 115° so that the antenna is circularly polarized.
Claim 11
Dependent Claim
42 words
The method of tilting the beam of a microstrip antenna claimed in claim 8, wherein the second distance is greater than the first distance and selected so that the impedances of the driven patch at the points of signal application are equal.
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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) | 1996-06-14 | 1996-12-14 | 1997-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-14 | 2000-12-14 | 2001-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-14 | 2004-12-14 | 2005-06-15 | $7700.00 | Window Closed / Lapsed |