Transmitter Ak

181 Pages·2010·19.55 MB·English

https://ntrs.nasa.gov/search.jsp?R=19840009409 2019-03-27T08:52:52+00:00Z
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Produced by the NASA Center for Aerospace Information (CASI)
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July 1983
Contract No. NAS3-22503
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Prepared for
National Aeronautics
and Space Administration
Lewis Research Center
C Cleveland, OH 44135
TRW Electronic
Systems Group
One Space Park
Redondo Beach, CA 90278
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20 GHz Spacecraft
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i FET Solid State
Transmitter
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Final Report
No. CR 168240
July 1083
Contract No. NAS3-?2503
Prepared for
National Aeronautics
and Space Administration
Lewis Research Center
Cleveland, OH 44135
By
J. Goel and S. Yuan
TRW Electronic
Systems Group
One Space Park
i Redondo Beach, CA 90278
i
ABSTRACT
This final report details the engineering development of a solid state
transmitter amplifier operating in the 20 GHz frequency band using GaAs
field effect transistors (FETs). The major efforts include GaAs FET device
development, single-ended amplifier stage, balanced amplifier stage,
cascaded stage and radial combiner designs, and amplifier integration and
test.
The result of this effort is the development of a multistage GaAs FET
amplifier capable of 8.2 W CW output over the 17.9 to 19.1 GHz frequency
band. The GaAs FET devices developed under this program represent state-
of-the-art FET power device technology. Further device improvements are
necessary to increase the bandwidth to 2.5 GHz, improve do-to-RF
efficiency, and increase power capability at the device level. Higher
power devices will simplify the amplifier combining scheme, reducing the
size and weight of the overall amplifier.
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PRECE
-))rNG PAGE BLANK IyW MUM
iii
I
CONTENT
Page
1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 1-1
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2. SYSTEM DESCRIPTION . . . . . . . . . . . . . . . . . . . . . 2-1
2.1 System Overview . . . . . . . . . . . . . . . . . . . . 2-1
2.1.1 System Block Diaqram . . . . 2-1
2.1.2 Driver Module and Power Module 2-1
V
t 2.2 Gain Budqet . . . . . . . . . . . . . . . . . . . . . . 2-4
2.3 Critical Circuit Elements . . . . . . . . . . . . . . . 2-4
3. NASA 20 GHz POWER GaAs FET DEVELOPMENT . . . . . . . . . . . 3-1
Y
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . 3-1
3.2 Design Considerations . . . . . . . . . . . . . . . . . 3-2
3.3 Fabrication Technology . . . . . . . . . . . . . . . . 3-6
3.4 DC Characterization . . . . . . . . . . . . . . . . 3-9
3.5 Thermal Characterization . . . . . . . . . . . . . . . 3-11
- 3.6 Design of 862, 872 and 900 Type Devices . . . . . . . . 3-13
_ 3.7 Wafer Processing Summary . . . . . . . . . . . . . . . 3-16
_ 3.8 RF Characterization . . . . . . . . . . . . . . . . . . 3-19
3.9 RF Performance . . . . . . . . . . . . . . . . . . . 3-23
3.9.1 862 and 872 Type Devices . . . . . . . . . . . . 3-23
3.9.2 900 Type Devices . . . . . . . . . . . . . . . . 3-26
3.10 Thermal Characterization Data . . . . . . . . . . . . . 3-29
3.11 Device Assembly and Delivery . . . . . . . . . . . . . 3-33
3.12 Conclusions and Summary . . . . . . . . . . . . . . . . 3-35
4. AMPLIFIER CIRCUIT DEVELOPMENT . . . . . . . . . . . . . . . 4-1
4.1 Waveguide-to-Microstrip Transition . . . . . . . . . . 4-1
4.1.1 Transition . . . . ' . . . . . . . . . . . . . . . 4-1
4.2 Lanqe Couplers . . . . . . . . . . . . . . . . . . . . 4-2
4.2.1 Coupler Design 4-2
4.2.2 Coupler Test Fixture 4-7
4.2.3 Coupler Test Data . . . . . . . . . . . . . . . 4-7

PAGk,.V _.INTENTIONALLY BLANK V 'R'ECEnrNG PAGE: BLANK NOT FU,'MED
CONTENT (Contined)
Page
4.3 Carriers . . . . . . . . . . . . . . . . . . . . . . . 4-7
4.3.1 FET Carrier Design . . . . . . . . . . . . . . 4-9
4.3.2 Thermal Considerations . . . . . . . . . . . . . 4-11
4.3.3 Carrier Assembly . . . . . . . . . . . . . . . . 4-11
4.4 Device Type . . . . . . . . . . . . . . . . . . . . . . 4-13
4.5 Single-Ended Amplifier . . . . . . . . . . . . . . . . 4-14
4.5.1 Device S-Parameters . . . . . . . . . . . . . . 4-14
4.5.z Device Operating Conditions . . . . . . . . . . 4-20
4.6 Driver Amplifier Module . . . . . . . . . . . . . . . . 4-33
4.6.1 Driver Module Specifications . . . . ... . . . . 4-33
4.6.2 Driver Module Design . . . . . . . . . . . . . . 4-33
4.6.3 Driver Module Integration . . . . . . . . . . . 4-36
4.6.4 Driver Module Test Data . . . . . . . . . . . . 4-36
4.7 Power Amplifier Module . . . . . . . . . . . . . . . . 4-39
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4.7.1 Power Module Specifications . . . . . . . . . . 4-39
3 `
4.7.2 Power Module Design . . . . . . . . . . . . 4-39
4.7.3 Power Module Integration . . . . . . . . . . . . 4-40
4.7.4 Power Module Test Data . . . . . . . . . . . . . 4-41
4.8 Cascaded Driver and Power Modules . . . . . . . . . . . 4-43 3
4.8.1 Module Design and Integration . . . . . . . . 4-43
4.8.2 Cascaded Module Specifications. . . . . . . 4-43
4.8.3 Cascaded Driver/Power Module Test D ata . . . . . 4-43
4.9 Radial Power Splitter/Combiner . . . . . . . . . . . . 4-47
4.9.1 General Discussion 4-47
4.9.2 assumptions and Criteria for Op*imization 4-48 -^
4.9.3 Power Dissipation in Isolation Resistor . . . . 4-51
4.9.4 Power Combining Losses . . . . . . . . . . . . . 4-53
4.9.5 Graceful Degradation . 4-56 ,, 1
4.9.6 Power Dissipation Data in^Various*Substrates 4-58
4.9.7 Radial Transmission Lire . . . . . . . . 4-58 -^
4.9.8 Coaxial to Radial Line Transition . . . . . . . 4-67
4.9.9 Splitter/Combiner Design . . . . . . . . . . . . 4-68 =' i
4.10 Eiqht-Way Combined Amplifier Module . . . . . . . . . . 4-74
..
4.10.1 Module Design 4-74
4.10.2 Amplitude/PhaseConfiguration 4-75 °-
4.10.3 Module Integration and Test Data . . . . . . . . 4-76
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CONTENT (Contined)
Page
j 4.11 Graceful Degradation . . . . . . . . . . . . . . . . . 4-79
4.12 Regulator . . . . . . . . . . . . . . . . . . . . . . . 4-80
4.12.1 Requl ator . . . . . . . . . . . . . . . . 4-80
4.12.2 Regulator Boards . . . . . . . . . . . . . . . . 4-82
3 4.13 Waveguide Mode Suppressor . . . . . . . . . . . . . . . 4-82
4.14 POC Amplifier Assembly ... . . . . . . . . . . . . . . 4-82
4.14.1 POC Assembly Design . . . . . . . . . . . . . . 4-82
4.14.2 POC Assembly Test Data . . . . . . . . . . . . . 4-86
_ 5. MECHANICAL CONSIDERATIONS . . . . . . . . . . . . . . . . . 5-1
5.1 Waveguide to Microstrip Transition . . . . . . . . . . 5-1
a 5.2 Lange Couplers . . . . . . . . . . . . . . . . . . . . 5-1
5.3 FET Carrier Design . . . . . . . . . . . . . . . . 5-10
5.4 Submodule Design . . . . . . . . . . . . . . . . . . . 5-10
5.5 Radial Splitter/Combiner . . . . . . . . . . . . . . . 5-15
5.6 Cascaded Driver/Power Module . . . . . . . . . . . . . 5-15
5.7 Eight-way Combined Amplifier . . . . . . . . . . . . . 5-24
5.8 Regulators . . . . . . . . . . . . . . . . . . . . . . 5-24
5.9 POC Amplfier Assembly . . . . . . . . . . . . . . . . . 5-24
5.10 Thermal Considerations . . . . . . . . . . . . . . . . 5-27
6. CONCLUSIONS AND RECOMMENDATIONS . . . . . . . . . . . . . . 6-1
^. 6.1 Conclusions . . . . . . . . . . . . . . . . . . . . . . 6-1
6.2 Recommendations . . . . . . . . . . . . . . . . . . . . 6-2
6.3 Acknowledgment . . . . . . . . . . . . . . . . . . . . 6-3
6.4 Engineers . . . . . . . . . . . . . . . . . . . . . . . 6-4
6.5 Technicians . . . . . . . . . . . . . . . . . . . . . 6-4
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CONTENT (Contined)
Page
APPENDICES
A. AN 18 GHz 8-WAY RADIAL COMBINER . . . . . . . . . . . . A-1
B. A 1 WATT GaAs POWER AMPLIFIER FOR THE NASA 30/20 GHz
COMMUNICATION SYSTEM . . . . . . . . . . . . . . . . B-1
C. AN 8.0 WATT K-BAND FET AMPLIFIER FOR SATELLITE
DOWNLINK . . . . . . . . . . . . . . . . . . . . . . C-1
J-^t
viii
1. INTRODUCTION
This report covers the work performed by TRW on the program Entitled,
"30/20 GHz Spacecraft GaAs FET Solid state Transmitter", under Contract No.
NAS3-22503 sponsored by National Aeronautics and Space Administration,
Lewis Research Center, Cleveland, OH 44135.
The objectives of this program are:
• Based on an assessment of the technology available by 1982, a 20
GHz GaAs transmitter shall be designed to provide 6 to 7.5 watts
(CW) over the frequency band of 17.7 to 20.2 GHz
• 20 GHz GaAs FET shall be designed and developed, and device
packaging and characterization shall be performed
9
A proof-of-concept (POC) model of the space-qualifiable 20 GHz GaAs
FET transmitter shall be developed and tested
• A reliability analysis on the POC model shall be performed
• A product assurance program shall be effected during fabrication of
the POC model
• A technology assessment shall be made to establish the available
device performance abilities as well as the growth prospects of
GaAs FET devices.
The POC model design qoals a •e shown in Table 1-1 below.
1-1
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Table 1-1. Design Goals for POC Model 20 GHz
Transmitter Amplifier
Frequency Band 17.7 to 20.2 GKz
Output Power 6 to 7.5 Watts
RF Gain at Po 30 dB minimum
Gain Flatness ±0.5 dB total
Gain Variation 0.15-dB per MHz
Input/Output VSWR <1.4
Noise Figure < 25 dB
Third Order IMD < 20 d3c at Po
< 30 dBc at Po/2
Group Delay Variation < 0.5 nsec per 0.5 GHz
AM/PM Conversion < 3° per dB above PO
2° per dB below Po
Phase Linearity < 5 PK-PK deviation
Harmonics <30 d"a : at Po
Spurious Response < 60 dBc at Po
RF Efficiency >13 percent
Projected life >10 years
Overdrive Limit > 24 mW
Temperature Range 0 to 75°C
1-2
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