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US4056785A
Expired / Lapsed
US
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Low-noise microwave amplifier
Assignee: AT&T Inc
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Filing: 1976-12-06
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Granted: 1977-11-01
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Expires: 1996-12-06
Abstract
Abstract An improved low-noise microwave amplifier comprises a circuit arrangement coupled in parallel with a GaAs FET amplifying stage for reducing transmission loss in case of dc power failure or amplifying stage failures. The circuit arrangement comprises two microwave circulators and a microwave isolator connected therebetween.
Inventors
- 👤 Clarence Burke Swan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:43
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/60; H03F3/601; H03F2200/00; H03F2200/198; H03F2200/372
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
161 words
A microwave amplifier comprising: an input microwave circulator having in the direction of circulation a first, second and third port; an output microwave coupling device having at least a first, second and third port; means for coupling an input signal to the first port of said input circulator; means for deriving an output signal from the second port of said output device; an amplifying stage having an input terminal and an output terminal; means for coupling said amplifying stage between the second port of said input circulator and the first port of said output device; and a passive signal by-pass arrangement coupled between the third ports of said input circulator and output device such that only under unpowered or otherwise failed condition of said amplifying stage said input signal is reflected at said input terminal and coupled to said output terminal via said input circulator, said passive by-pass arrangement and said output coupling device thereby reducing transmission loss of the amplifier.
Claim 2
Dependent Claim
161 words
A microwave amplifier comprising: an input microwave circulator having in the direction of circulation a first, second and third port; an output microwave coupling device having at least a first, second and third port; means for coupling an input signal to the first port of said input circulator; means for deriving an output signal from the second port of said output device; an amplifying stage having an input terminal and an output terminal; means for coupling said amplifying stage between the second port of said input circulator and the first port of said output device; and a passive signal by-pass arrangement coupled between the third ports of said input circulator and output device such that only under unpowered or otherwise failed condition of said amplifying stage said input signal is reflected at said input terminal and coupled to said output terminal via said input circulator, said passive by-pass arrangement and said output coupling device thereby reducing transmission loss of the amplifier.
Claim 3
Dependent Claim
147 words
A microwave amplifier comprising: input and output microwave circulators, each having in the direction of circulation a first, second and third port; means for coupling an input signal to the first port of said input circulator; means for deriving an output signal from the second port of said output circulator; an amplifying stage having an input terminal and an output terminal; means for coupling said amplifying stage between the second port of said input circulator and the first port of said output circulator; and a passive signal by-pass arrangement coupled between the third ports of said input and output circulators such that only under unpowered or otherwise failed condition of said amplifying stage said input signal is reflected at said input terminal and coupled to said output terminal via said input circulator, said passive by-pass arrangement and said output circulator thereby reducing transmission loss of the amplifier.
Claim 4
Dependent Claim
147 words
A microwave amplifier comprising: input and output microwave circulators, each having in the direction of circulation a first, second and third port; means for coupling an input signal to the first port of said input circulator; means for deriving an output signal from the second port of said output circulator; an amplifying stage having an input terminal and an output terminal; means for coupling said amplifying stage between the second port of said input circulator and the first port of said output circulator; and a passive signal by-pass arrangement coupled between the third ports of said input and output circulators such that only under unpowered or otherwise failed condition of said amplifying stage said input signal is reflected at said input terminal and coupled to said output terminal via said input circulator, said passive by-pass arrangement and said output circulator thereby reducing transmission loss of the amplifier.
Claim 5
Dependent Claim
17 words
A microwave amplifier according to claim 2 wherein said signal by-pass arrangement comprises a microwave nonreciprocal device.
Claim 6
Dependent Claim
49 words
A microwave amplifier according to claim 3 wherein said nonreciprocal device comprises a three-port circulator having its first port coupled to said third port of the input circulator, its second port coupled to said third port of the output circulator and its third port coupled to a termination impedance.
Claim 7
Dependent Claim
27 words
A microwave amplifier according to claim 3 wherein said signal by-pass arrangement further comprises filtering and/or length adjusting means for modifying the phase of the by-pass signals.
Claim 8
Dependent Claim
110 words
A low-noise microwave amplifier comprising: input and output microwave circulators, each having in the direction of circulation a first, second and third port; means for coupling an input signal to the first port of said input circulator; means for deriving an output signal from the second port of said output circulator; means for coupling a GaAs FET amplifying device between the second port of said input circulator and the first port of said output circulator; and a passive signal by-pass arrangement coupled between the third ports of said input and output circulators for reducing transmission loss of the amplifier only under unpowered or otherwise failed condition of said amplifying device.
Claim 9
Dependent Claim
110 words
A low-noise microwave amplifier comprising: input and output microwave circulators, each having in the direction of circulation a first, second and third port; means for coupling an input signal to the first port of said input circulator; means for deriving an output signal from the second port of said output circulator; means for coupling a GaAs FET amplifying device between the second port of said input circulator and the first port of said output circulator; and a passive signal by-pass arrangement coupled between the third ports of said input and output circulators for reducing transmission loss of the amplifier only under unpowered or otherwise failed condition of said amplifying device.
Claim 10
Dependent Claim
36 words
A low-noise microwave amplifier according to claim 6 wherein said by-pass arrangement comprises a microwave isolator for unidirectionally coupling input signals reflected at the device input terminal to the device output terminal via said output circulator.
References Cited (Backward Citations)
US3857106A
Cited
US3992669A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-31 | 1981-05-02 | 1981-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-31 | 1985-05-02 | 1985-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-31 | 1989-05-02 | 1989-11-01 | $7700.00 | Window Closed / Lapsed |