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US4843400A
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US
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Aperture coupled circular polarization antenna
Assignee: Lanteris Space LLC
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Filing: 1988-08-09
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Granted: 1989-06-27
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Expires: 2008-08-09
Abstract
Abstract A generally planar antenna for generating circularly polarized electromagnetic signals, particularly useful at microwave frequencies. Each antenna element comprises a single excitation aperture (7) cut in a planar conductive ground plane (9). Spaced apart from the ground plane (9) by means of a dielectric layer (11) and covering the excitation aperture (7) is a planar conductive radiating patch (5) having slightly different dimensions along each of two orthogonal axes. The radiating patch (5) may have the shape of a near square or an ellipse. Exciting the aperture (7) with linearly polarized electromagnetic energy causes the radiating patch (5) to generate a circularly polarized electromagnetic signal consisting of two orthogonal components that have substantially the same amplitude and are 90° offset in phase from each other. Several antenna elements can be combined to form a large aperture array. Energy may be applied to the excitation aperture (7) by means of a waveguide (3) feed, microstrip line (15), or stripline (15).
Inventors
- 👤 Chich-Hsing Tsao
- 👤 Thomas E. Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:05
CPC Classifications
H; H01; H01Q; H01Q21/00; H01Q21/06; H01Q21/061; H01Q21/065; H01Q9/00; H01Q9/04; H01Q9/0407; H01Q9/0428
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
166 words
An antenna element for generating circularly polarized electromagnetic signals, comprising: a single elongated excitation aperture cut in a planar conductive ground plane; in spaced parallel relation to the ground plane and completely covering the excitation aperture when viewed from a direction orthogonal to the ground plane, a planar conductive radiating patch havng slightly different dimensions along each of two orthogonal axes, with each said dimension being greater than the length of the excitation aperture; and a first planar dielectric layer separating the ground plane and the aperture from the radiating patch; wherein the excitation aperture forms an angle of substantially 45°, viewed from a direction orthogonal to the plane of the radiating patch, with respect to each of the two orthogonal axes of the radiating patch; whereby exciting the aperture with linearly polarized electromagnetic energy causes the radiating patch to generate a circularly polarized electromagnetic signal consisting of two orthogonal cmponents that have substantially the same amplitude and are 90° offset in phase from each other.
Claim 2
Dependent Claim
166 words
An antenna element for generating circularly polarized electromagnetic signals, comprising: a single elongated excitation aperture cut in a planar conductive ground plane; in spaced parallel relation to the ground plane and completely covering the excitation aperture when viewed from a direction orthogonal to the ground plane, a planar conductive radiating patch havng slightly different dimensions along each of two orthogonal axes, with each said dimension being greater than the length of the excitation aperture; and a first planar dielectric layer separating the ground plane and the aperture from the radiating patch; wherein the excitation aperture forms an angle of substantially 45°, viewed from a direction orthogonal to the plane of the radiating patch, with respect to each of the two orthogonal axes of the radiating patch; whereby exciting the aperture with linearly polarized electromagnetic energy causes the radiating patch to generate a circularly polarized electromagnetic signal consisting of two orthogonal cmponents that have substantially the same amplitude and are 90° offset in phase from each other.
Claim 3
Dependent Claim
20 words
The apparatus of claim 1 wherein the radiating patch has the shape of a rectangle that is nearly a square.
Claim 4
Dependent Claim
40 words
The apparatus of claim 2 wherein each side of the rectangle has a length approximately equal to half of a wavelength of the electromagnetic signal generated by the antenna, said wavelength taking into account the presence of the dielectric layer.
Claim 5
Dependent Claim
30 words
The apparatus of claim 1 wherein the radiating patch has the shape of an ellipse, and the angle between the aperture and the major axis of the ellipse is 45°.
Claim 6
Dependent Claim
19 words
The apparatus of claim 1 wherein the ground plane constitutes one of four walls of an elongated conductive waveguide.
Claim 7
Dependent Claim
44 words
The apparatus of claim 1 further comprising a second planar dielectric layer having first and second sides, the first side touching a surface of the ground plane that is not touching the first dielectric layer and the second side supporting a microstrip feed network.
Claim 8
Dependent Claim
44 words
The apparatus of claim 1 further comprising a second planar dielectric layer having first and second sides, the first side touching a surface of the ground plane that is not touching the first dielectric layer and the second side supporting a stripline feed network.
Claim 9
Dependent Claim
29 words
Apparatus comprising several antenna elements of claim 1 combined in an array having a repeating geometrical pattern and an aperture larger than the aperture of any single antenna element.
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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) | 1992-06-26 | 1992-12-26 | 1993-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-26 | 1996-12-26 | 1997-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-26 | 2000-12-26 | 2001-06-27 | $7700.00 | Window Closed / Lapsed |