design of power-scalable gallium nitride class e power amplifiers

117 Pages·2014·1.89 MB·English

DESIGN OF POWER-SCALABLE GALLIUM NITRIDE
CLASS E POWER AMPLIFIERS
Thesis
Submittedto
TheSchoolofEngineeringofthe
UNIVERSITYOFDAYTON
InPartialFulfillmentoftheRequirementsfor
TheDegreeof
MasterofScienceinElectricalEngineering
By
MarkAnthonyConnor
UNIVERSITYOFDAYTON
Dayton,Ohio
August, 2014
DESIGNOFPOWER-SCALABLEGALLIUMNITRIDECLASSEPOWER
AMPLIFIERS
Name: Connor,MarkAnthony
APPROVEDBY:
GuruSubramanyam,Ph.D. RobertPenno,Ph.D.
AdvisorCommitteeChairman CommitteeMember
ChairpersonandProfessor,Department Professor,DepartmentofElectricaland
ofElectricalandComputerEngineering ComputerEngineering
WeisongWang,Ph.D.
CommitteeMember
ResearchEngineer,Departmentof
ElectricalandComputerEngineering
JohnG.Weber,Ph.D. EddyM.Rojas,Ph.D.,M.A.,P.E.
AssociateDean Dean
SchoolofEngineering SchoolofEngineering
ii
(cid:13)c Copyrightby
MarkAnthonyConnor
Allrightsreserved
2014
ABSTRACT
DESIGNOFPOWER-SCALABLEGALLIUMNITRIDECLASSEPOWERAMPLIFIERS
Name: Connor,MarkAnthony
UniversityofDayton
Advisor: Dr. GuruSubramanyam
The need for high power, highly efficient, multi-band and multi-mode radio frequency (RF)
and microwave power amplifiers in the commercial and defense wireless industries continues to
drive the research and development of gallium nitride (GaN) devices and their implementation in
the receiver and transmitter lineups of modern microwave systems. Unlike silicon (Si) or gallium
arsenide (GaAs), GaN is a direct wide bandgap semiconductor that permits usage in high voltage
andthereforehighpowerapplications. Additionally,theincreasedsaturationvelocityofGaNallows
for operation well into the super high frequency (SHF) portion of the RF spectrum. For the power
amplifier designer, active devices utilizing GaN will exhibit power densities almost an order of
magnitudegreaterthancomparablysizedGaAsdevicesandalmosttwoordersofmagnitudegreater
thanSidevices. Notonlydoesthismeananoverallsizereductionofanamplifierforagivenoutput
power,butitallowsGaNtoreplacespecializedcomponentssuchasthetraveling-wavetube(TWT)
andothercircuitsoncedeemedimpossibletorealizeusingsolid-stateelectronics. Designsutilizing
GaNinamplifiers,switches,mixers,etc.,areabletomeetthecontinuallyshrinkingsize,increased
power,stringentthermal,andcostrequirementsofamodernmicrowavesystem.
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Therearetworelativelystraightforwardmethodsusedtoinvestigatetheintrinsicpowerscaling
properties of a GaN high-electron-mobility transistor (HEMTs) configured as a common source
amplifier. The first method involves sweeping the applied drain to source voltage bias and the
secondmethodinvolvesscalingthephysicalsizeofthetransistor. Thepriormethodcanbeusedto
evaluate fixed sized transistors while the latter method requires an understanding of the obtainable
power density for a given device technology prior to fabrication. Since the power density is also a
functionofthedraintosourcevoltagebias,aninitialiterativecomponentofthedesigncyclemaybe
requiredtofullycharacterizethedevicetechnology. Ifascalablenonlineardevicemodelisavailable
tothedesigner,theharmonicbalancesimulatorinmostcomputeraideddesign(CAD)toolscanbe
usedtoevaluatedeviceparameterssuchasthemaximumoutputpowerandpoweraddedefficiency
(PAE)usinglargesignalloadpullsimulations.
Thecircuitspresentedinthisthesisaddresstwopoweramplifierdesignapproachescommonly
usedinindustry. ThefirstapproachutilizescommerciallyavailablebaredieGaNtransistorsthatcan
bewire-bondedtomatchingcircuitryonaprintedcircuitboard(PCB).Thistechniqueisknownas
hybridpackaging. Thesecondapproachutilizesafullyintegrateddesignormonolithicmicrowave
integrated circuit (MMIC) and the process design kit (PDK) used to design, simulate and layout
the power amplifier circuitry before submission to a foundry for fabrication. In both cases, the
nonlineartransistormodelsareusedtoinvestigatethepowerscalabilityofclassEmodeGaNpower
amplifiers and the techniques used to implement such circuits. The design, results, and challenges
ofeachapproacharediscussedandfutureworkispresented.
iv
Tothescientists,mathematiciansandengineerswhocamebeforeus,forwetrulystandonthe
shouldersofgiants.
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ACKNOWLEDGMENTS
I would like to thank Dr. Guru Subramanyam, my undergraduate and graduate advisor, for all
thesupporthehasgivenmesincemyfirstsemesterattheUniversityofDaytoninthefallof2008.
If it were not for his desire to see me succeed in every academic and professional endeavor I have
undertaken, I would not have pursued an advanced degree in electrical engineering. He graciously
welcomedmeintohismicrowaveengineeringgroupasagraduatestudentafterprovidingmewitha
solidfoundationinmicroelectronicsasanundergraduate. Icannotthankhimenoughforeverything
thathehasdoneformeandtheUniversityofDayton.
I am thankful for all of my family and friends; past and present, who have helped me become
thepersonIamtoday. Ittakesacaringindividualtohaveagenuineinterestinanother’sobsession
with electronics. Likewise, thank you to all of my professors who have encouraged me to go be-
yond the classroom and apply what I have learned. Additionally, I would like to thank all of my
former coworkers and mentors while employed as an intern and co-op student; the practical work
experience gained under your supervision has been an invaluable asset and a driving force for my
future.
Finally, I would like to thank my additional committee members, Dr. Robert Penno and Dr.
WeisongWang,fortheirsupportbyreviewingmyworkandprovidingpositiveyetstablefeedback.
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TABLEOFCONTENTS
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
DEDICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
ACKNOWLEDGMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
LISTOFFIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
LISTOFTABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiv
I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 PowerScaling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
II. CLASSEAMPLIFIERDESIGNTECHNIQUES . . . . . . . . . . . . . . . . . . . . 6
2.1 SwitchModePowerAmplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 LoadPullCharacterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3 Small-SignalConsiderations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4 DeviceSelection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
III. HYBRIDPACKAGINGDESIGNAPPROACH . . . . . . . . . . . . . . . . . . . . . 14
3.1 TransistorIVCurves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.2 TransistorStability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.3 TransistorLoadPulls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.4 MicrowaveSubstrateLaminate . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.5 WilkinsonPowerSplitter/Combiner . . . . . . . . . . . . . . . . . . . . . . . . 29
3.6 GateandDrainBiasNetworks . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.7 SingleTransistorInputandOutputMatching . . . . . . . . . . . . . . . . . . . 33
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3.8 SingleTransistorPowerAmplifiers . . . . . . . . . . . . . . . . . . . . . . . . 39
3.9 ParallelTransistorPowerAmplifiers . . . . . . . . . . . . . . . . . . . . . . . . 45
IV. MMICDESIGNAPPROACH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.1 TransistorIVCurves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.2 TransistorStability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.3 TransistorLoadPull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.4 Single2.5WMMICPowerAmplifier . . . . . . . . . . . . . . . . . . . . . . . 55
4.5 MicrowaveSPDTSwitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
4.6 CombinedImpedanceSelector . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
4.7 ReconfigurableMMICPowerAmplifier . . . . . . . . . . . . . . . . . . . . . . 66
V. HYBRIDPACKAGINGSIMULATIONANDRESULTS . . . . . . . . . . . . . . . . 68
5.1 WilkinsonPowerSplitter/Combiner . . . . . . . . . . . . . . . . . . . . . . . . 68
5.2 GateandDrainBiasNetworks . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
5.3 SingleTransistorPowerAmplifiers . . . . . . . . . . . . . . . . . . . . . . . . 70
5.4 ParallelTransistorPowerAmplifiers . . . . . . . . . . . . . . . . . . . . . . . . 76
VI. MMICSIMULATIONANDRESULTS . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.1 Single2.5WPowerAmplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.2 MicrowaveSPDTSwitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.3 CombinedImpedanceSelector . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.4 ReconfigurableMMICPowerAmplifier-SingleDeviceOn . . . . . . . . . . . 87
6.5 ReconfigurableMMICPowerAmplifier-BothDevicesOn . . . . . . . . . . . 91
VII. CONCLUSIONSANDRECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . 97
7.1 Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
7.2 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
viii
LISTOFFIGURES
2.1 GenericPAblockdiagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 ScalablePAblockdiagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 Baredie(1.25mm)DCsweepschematic[1] . . . . . . . . . . . . . . . . . . . . . 14
3.2 Baredie(1.25mm)IVcurves[1] . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3 Baredie(2.5mm)DCsweepschematic[1] . . . . . . . . . . . . . . . . . . . . . . 16
3.4 Baredie(2.5mm)IVcurves[1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.5 Baredie(5mm)DCsweepschematic[1] . . . . . . . . . . . . . . . . . . . . . . . 18
3.6 Baredie(5mm)IVcurves[1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.7 Baredie(1.25mm)stabilityschematic[1] . . . . . . . . . . . . . . . . . . . . . . 20
3.8 Baredie(1.25mm)geometricstabilityevaluation[1] . . . . . . . . . . . . . . . . 21
3.9 Baredie(2.5mm)stabilityschematic[1] . . . . . . . . . . . . . . . . . . . . . . . 22
3.10 Baredie(2.5mm)geometricstabilityevaluation[1] . . . . . . . . . . . . . . . . . 23
3.11 Baredie(5mm)stabilityschematic[1] . . . . . . . . . . . . . . . . . . . . . . . . 24
3.12 Baredie(5mm)geometricstabilityevaluation[1] . . . . . . . . . . . . . . . . . . 25
3.13 Baredie(1.25mm)classEloadpull[1] . . . . . . . . . . . . . . . . . . . . . . . 26
3.14 Baredie(2.5mm)classEloadpull[1] . . . . . . . . . . . . . . . . . . . . . . . . 27
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