US3898663A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Retrodirective transponder
Assignee: United States Department of the Air Force
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Filing: 1970-04-01
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Granted: 1975-08-05
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Expires: 1990-04-01
Abstract
Abstract A retrodirective transponder wherein pairs of elementary radiators are connected by equal lengths of transmission lines so that the re-radiated wavefront is parallel to the incident wave front permitting the re-radiated signal to be beamed in the direction of the illuminating transmitters. The re-radiated wavefront is frequency translated from the incident wave to avoid ringing of the transponder.
Inventors
- 👤 Joseph J Albert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:53
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/82
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
184 words
A retrodirective transponder comprising a retrodirective antenna array having at least first and second receiving antennas receiving a signal from an illuminating transmitter, at least first and second transmitting antennas re-radiating a signal parallel to the received signal and towards said illuminating transmitter, said first receiving and transmitting antennas being a first pair and said second receiving and transmitting antennas being a second pair, a first cascaded electrical loop interconnecting said first receiving and transmitting antennas consisting of a first mixer, a first amplifier, a first preselected frequency multiplier, a second amplifier, and a second mixer, a second cascaded electrical loop interconnecting said second receiving and transmitting antenna, said second cascaded electrical loop consisting of a third mixer, a third amplifier, a second preselected frequency multiplier, a fourth amplifier, and a fourth mixer, said first and second cascaded electrical loops being of equal length, a common local oscillator having a predetermined frequency output signal, said predetermined frequency output signal being injected into said first and third mixers, and a third preselected frequency multiplier interconnecting said common local oscillator and said second and fourth mixers.
Claim 2
Dependent Claim
184 words
A retrodirective transponder comprising a retrodirective antenna array having at least first and second receiving antennas receiving a signal from an illuminating transmitter, at least first and second transmitting antennas re-radiating a signal parallel to the received signal and towards said illuminating transmitter, said first receiving and transmitting antennas being a first pair and said second receiving and transmitting antennas being a second pair, a first cascaded electrical loop interconnecting said first receiving and transmitting antennas consisting of a first mixer, a first amplifier, a first preselected frequency multiplier, a second amplifier, and a second mixer, a second cascaded electrical loop interconnecting said second receiving and transmitting antenna, said second cascaded electrical loop consisting of a third mixer, a third amplifier, a second preselected frequency multiplier, a fourth amplifier, and a fourth mixer, said first and second cascaded electrical loops being of equal length, a common local oscillator having a predetermined frequency output signal, said predetermined frequency output signal being injected into said first and third mixers, and a third preselected frequency multiplier interconnecting said common local oscillator and said second and fourth mixers.
Claim 3
Dependent Claim
158 words
A retrodirective transponder comprising a retrodirective antenna array having at least first and second receiving antennas receiving a signal from an illuminating transmitter, at least first and second transmitting antennas re-radiating a signal parallel to the received signal and toward said illuminating transmitter, said first receiving and transmitting antennas being a first pair and said second receiving and transmitting antennas being a second pair, a first cascaded loop interconnecting said first receiving and transmitting antennas and consisting of a first mixer, a first amplifier, a first multiplier, a second multiplier, a first filter, a third multiplier, a second amplifier, and a second mixer, a second cascaded loop interconnecting said second receiving antenna and transmitting antenna and consisting of a third mixer, a third amplifier, a fourth multiplier, a fifth multiplier, a second filter, a sixth multiplier, a fourth amplifier, a fourth mixer, and a pseudo-random generator providing simultaneously output signals to said first, third, fourth, and sixth multipliers.
Claim 4
Dependent Claim
158 words
A retrodirective transponder comprising a retrodirective antenna array having at least first and second receiving antennas receiving a signal from an illuminating transmitter, at least first and second transmitting antennas re-radiating a signal parallel to the received signal and toward said illuminating transmitter, said first receiving and transmitting antennas being a first pair and said second receiving and transmitting antennas being a second pair, a first cascaded loop interconnecting said first receiving and transmitting antennas and consisting of a first mixer, a first amplifier, a first multiplier, a second multiplier, a first filter, a third multiplier, a second amplifier, and a second mixer, a second cascaded loop interconnecting said second receiving antenna and transmitting antenna and consisting of a third mixer, a third amplifier, a fourth multiplier, a fifth multiplier, a second filter, a sixth multiplier, a fourth amplifier, a fourth mixer, and a pseudo-random generator providing simultaneously output signals to said first, third, fourth, and sixth multipliers.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |