US5208554A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High power compact microwave amplifier
Assignee: ST SYSTRON DONNER Corp
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Filing: 1992-01-24
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Granted: 1993-05-04
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Expires: 2012-01-24
Abstract
Abstract A Class A high power amplifier having an operating frequency in the range of less than substantially 2 GHz and suitable for aircraft use, is all solid state in that gallium arsenide field effect transistors are utilized. These are mounted in a large copper heat sink which is air cooled to provide for overall cooling by conduction and convection. By the use of microstrip matching circuits, the relatively low impedance of the gallium arsenide FET units is matched to the required higher system impedance. At the same time a 40% band-width is provided due to the superior matching.
Inventors
- 👤 Harvey Endler
- 👤 Hadi Mojaradi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 23:06
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/60; H03F3/602; H03F3/604
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
191 words
A class A power amplifier having an operating frequency in the range of less than substantially 2 GHz comprising: a plurality of parallel connected gallium arsenide (GaAs) field effect transistors (FETs) providing a high power output in the range of at least 100 watts, said FETs having a relatively low input and output impedance compared to a required normal relatively high system impedance; a microstrip matching circuit mounted on a dielectric substrate for matching said relatively high system impedance to said input and output impedance of said FETs, each substrate being dimensioned in accordance with the frequency 2 GHz or less, said substrates being substantially 1 by 1 inch in size; a plurality of conductive bases for providing a thermal expansion match with said dielectric substrate, said conductive bases also providing a direct mounting surface for said plurality of FETs, each of said bases carrying a pair of said FETs along with said microstrip matching circuits carried on said dielectric substrates; heat sink means for cooling said FETs including a unitary copper base in which said FETs are inset via said conductive base whereby cooling is accomplished by at least conduction.
Claim 2
Dependent Claim
191 words
A class A power amplifier having an operating frequency in the range of less than substantially 2 GHz comprising: a plurality of parallel connected gallium arsenide (GaAs) field effect transistors (FETs) providing a high power output in the range of at least 100 watts, said FETs having a relatively low input and output impedance compared to a required normal relatively high system impedance; a microstrip matching circuit mounted on a dielectric substrate for matching said relatively high system impedance to said input and output impedance of said FETs, each substrate being dimensioned in accordance with the frequency 2 GHz or less, said substrates being substantially 1 by 1 inch in size; a plurality of conductive bases for providing a thermal expansion match with said dielectric substrate, said conductive bases also providing a direct mounting surface for said plurality of FETs, each of said bases carrying a pair of said FETs along with said microstrip matching circuits carried on said dielectric substrates; heat sink means for cooling said FETs including a unitary copper base in which said FETs are inset via said conductive base whereby cooling is accomplished by at least conduction.
Claim 3
Dependent Claim
40 words
A power amplifier as in claim 1 in which the relatively low input and output impedances of said GaAs, FETs are in the range of 2 to 3 ohms and said required normal relatively high system impedance is 50 ohms.
Claim 4
Dependent Claim
26 words
A power amplifier as in claim 1 in which said microstrip matching circuit includes distributed inductive and capacitive elements in microstrip form on said dielectric substrates.
Claim 5
Dependent Claim
23 words
A power amplifier as in claim 3 where said matching microstrip circuit includes a U-shaped configuration for providing said inductive and capacitive elements.
Claim 6
Dependent Claim
33 words
A power amplifier as in claim 1 in which said microstrip matching circuit also includes in addition to said elements in microstrip form, lumped inductor and capacitor units placed on said dielectric substances.
Claim 7
Dependent Claim
20 words
A power amplifier as in claim 1 including air blower means for providing convection cooling for said heat sink means.
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) | 1996-05-03 | 1996-11-02 | 1997-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-03 | 2000-11-02 | 2001-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-03 | 2004-11-02 | 2005-05-04 | $7700.00 | Window Closed / Lapsed |