US3803618A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multimodal retrodirective array
Assignee: United States Department of the Navy
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Filing: 1973-04-25
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Granted: 1974-04-09
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Expires: 1993-04-25
Abstract
Abstract A technique and apparatus for obtaining automatic retrodirective performance from antennas and antenna arrays of general geometric configurations such as cones, ellipsoids, etc. The elements of the antennas or arrays are connected to multimodal feed networks. Conjugate phase circuits and gain adjustments are connected to some of the feed network terminals. The degree of retrodirectivity can be controlled by the gain adjustment and the number of conjugate phase circuits used.
Inventors
- 👤 H Coleman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:50
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/26; H01Q3/2605; H01Q3/2647
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
86 words
A retrodirective antenna system of general geometric configuration comprising: a plurality of stacked circularly symmetric antennas; a like plurality of multimodal feed networks having antenna terminals and mode terminals, each symmetric antenna being associated with one of said multimodal networks; means for connecting each individual antenna in each symmetric antenna to the antenna terminals of the associated network; and, means connected to the mode terminals of said networks for receiving a signal from a terminal and returning to the terminal the phase conjugate of said signal.
Claim 2
Dependent Claim
86 words
A retrodirective antenna system of general geometric configuration comprising: a plurality of stacked circularly symmetric antennas; a like plurality of multimodal feed networks having antenna terminals and mode terminals, each symmetric antenna being associated with one of said multimodal networks; means for connecting each individual antenna in each symmetric antenna to the antenna terminals of the associated network; and, means connected to the mode terminals of said networks for receiving a signal from a terminal and returning to the terminal the phase conjugate of said signal.
Claim 3
Dependent Claim
15 words
The retrodirective antenna system of claim 1 wherein said circularly symmetric antennas are circular arrays.
Claim 4
Dependent Claim
16 words
The retrodirective antenna system of claim 1 wherein said circularly symmetric antennas are continuous aperture antennas.
Claim 5
Dependent Claim
18 words
The retrodirective antenna system of claim 1 wherein each of said multimodal feed networks is a Butler-Shelton matrix.
Claim 6
Dependent Claim
18 words
The retrodirective antenna system of claim 1 wherein each of said circularly symmetric antennas has a different axis.
Claim 7
Dependent Claim
19 words
The retrodirective antenna system of claim 2 wherein each of said circular arrays has a different number of elements.
Claim 8
Dependent Claim
26 words
The retrodirective antenna system of claim 1 wherein said signal receiving and returning means includes at least one conjugate phase circuit and one gain adjustment circuit.
Claim 9
Dependent Claim
29 words
The retrodirective antenna system of claim 7 wherein those mode terminals which are not connected to a conjugate phase circuit and gain adjustment circuit are terminated in matched loads.
References Cited (Backward Citations)
US3618090A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-08 | 1977-10-08 | 1978-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-08 | 1981-10-08 | 1982-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-08 | 1985-10-08 | 1986-04-09 | $7700.00 | Window Closed / Lapsed |