mit radiaton lab series, v7, klystrons and microwave triodes - front matter, preface, contents

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MASSACHUSETTS IA’S TIT1’TE OF TECHNOLOGY

RADIATION LABORATORY SERIES

Board of Editors

LOUIS X. I? IDE NOUR , .!lcii(or -zn -~lr ie f

GEORGEB. COLI.IXS, Dep!{@E ditor-in-(7hief

l lRITTON CHANCE,. A. GOLTDSMIT,. G. HERB,HUBERTLl. J AFiES,ULIANK. KNIP I,,

J AMESL.L.4WSON,EONB. LINFORD,AROLG.XI ONTGOMERY, C. NEWTON, ALBEBT

Tf. STONE , I,OCIS .4. TLV+NER , GEORGE E . VALLEY, J R., HERBERT H . ITHEATON

1. RADAR SYSTEM ~xG1x~ER1xG—Ridcnour

2’. R ADAR AIDS TO h -AvIGATIox—H all

3 . RAD .*RBEAroNs—RobeT~s

4, LORAN—P iWC6, McKen zie, an d Woodwai-d

5. P ULSE GENERATORS-Gk2S0 f?a n d LebaCqZ

6. b ~lC RO WAVE h lAGNE TR ONS—COllin S

i’. KLYSTRONS AND k hCROWAVE TRIoDEs—Ha mi!t on , Knipp, a n d Kuper

8. P RINCIP LESOF MICR OWAVE CIRcc,lTs—,lfo71 tgonLcry, Dicke, and Purcel l

9. h ~ICROWAVE TRANSMISSION CIRcu lTs— Ra ga n

10, ~VAVE GU ID E H AND BO OK—k fa TC Ut ik

11. -. . . . “,

12.

13.

14.

15.

16.

17.

18,

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

lE CHNIQUE OF lV1lCR OWAVE lVIE ASLTR EME NTS—l}~ On [gO~er V

n ~lCROWAVE ANTENNA THEORY AXD DESIGN—SdWr

P ROP AGATION OF SHORT RADIO 11’AVES—~W

\ ~ICROWAVE DUFLEXERS—S7Ru l/2n and ~f07i!y0mef y

CRYSTAL RECTIF IERS— To?r ey an d Wh itm er

}fIC RO WAVE n flXE RS—pOUn d

COMPONENTS HANDBOOK—~[aCkkn

VACUUM TUBE .k MF LIF IE RS-VU[/e ~ and bt-al[man

wAVEFORMS-ChanCE, Hughes, MacXichol, S ayre, and William s

ELECTRONIC TIME MEASUREMENTS- ChUnCf’, Hulsiar , Mach’ichol ,

a n d Wil[iams

ELECTRONIC I iYSTRUMENTS-(%’t 7LW00d , Ho[dam, a nd .l[a cf?a e

CATHODE RAY TUBE DISP LAYS—ISO/1~~, ,~farr, an d J ’cd ky

MlcROwAvE I iEcmv i3Rs-Van J -oorhis

THRESHOLD S IGSALs—LawsOn and [.”h lenbeck

TH EOR Y OF Se rvom ech a n ism s—J a m e s, ,Vichols, a n d Phillips

RADAR SCAXNERS AND RADoMEs—Ca dy, Karelifz, and T urn er

COMITTING ~~E CH ANISMS AND LINICAGE S--6’L>o b0d U

lx D Ex—H en n e y



KLYSTRONS AND

MICROWAVE .TRIODES

By

R. HAMILTON

PHYSICS, PRINCETON IJNIVERSITY

DONALD

AsSISTANT PROFESSOR OF

JULIAN K. KNIPP

ASSOCIATE PnOFESSOH OF PHYSICS, 10WA STATE COLLEGE

- J. B. HORNER KUPERBROOKHAVEN NATIONAL LABORATORY -

EDITORAL STAFF

GEOWHB. COLLINS ALBERT G. HILL. WINIFREDMCCULLOCH

oFFICE OF SCIEN~IFIC RESEARCH ANI) DEVELOPMENT

NA~IONAL DEFENSE RESEARCH COMMITTEE

FIRST EDITION

NEW YORK . TORONTO LONDON

MCGRA W-HILL BOOK COMPA N }’, INC.

194s



KLYSTRONS AND MICROWAVE TRIODES

COPYRIGHT, 1948, BY THE

MCGRAW-HILL BOOK (2 0 MPANY, INC,

PRINTED IN THE UNITED STATES OF AMERIcA

All righls reseroed. This book , orpart s !hereo j, may nol be reproduced

in any form wdhou( perrnissionoj

llte publishers.

THE MAPLE PRESS COMPANY, YORK, PA



Foreword

THE t r emendous research and development effor t that went in to the

development of radar and rela ted techniques dur ing Wor ld War II

resulted not on ly in hundreds of radar sets for military (and some for

possible peacet ime) use but also in a grea t body of informat ion and new

techniques in the elect ron ics and high-frequency fields. Because this

basic mater ia l may be of grea t va lue t o science and engin eer ing, it seemed

most impor tan t to publish it as soon as secur ity permit ted.

The Radia t ion Labora tory of MIT, which opera ted under the super-

vision of th e Nat ional Defen se Resear ch Commit tee, u nder took th e gr ea t

t ask of pr epa ring t h ese volumes. Th e wor k descr ibed h er ein , h owever , is

the collect ive resu lt of work done a t many laborator ies, Army, Navy,

university, and industr ia l, both in this count ry and in England, Canada,

and other Domin ions.

The Radiat ion Labora tory, once its proposa ls were approved and

fin an ces pr ovided by t he Office of Scien tific Resea rch a nd Developmen t,

chose Louis N. Ridenour as Editor -in-Chief to lead and direct the en t ire

project . An editor ia l staff was then selected of those best qualified for

this type of task. Finally the authors for the var ious volumes or chapter s

or sect ions wer e chosen from among those exper t s who were int imately

familiar with the var ious fields, and who were able and willing to wr ite

the summaries of them. This en t ire staff agreed to remain a t work at

MIT for six months or more after the work of the Radiat ion Labora tory

was complete. These volumes stand as a monument to this group.

These volumes serve as a memorial to the unnamed hundreds and

thousands of ot her scient ist s, en gineers, and oth er s wh o actua lly carr ied

on th e r esearch, development , and en gin eer ing wor k the result s of which

are herein descr ibed. There were so many involved in this work and they

wor ked so closely t oget her even t hou gh oft en in widely sepa ra ted la bor a-

tor ies tha t it is impossible to name or even t o kn ow th ose wh o cont r ibuted

t o a pa rt icu la r idea or developmen t. On ly cer ta in on es who wr ot e r epor ts

or ar t icles have even been ment ioned. But to all those who cont r ibuted

in any way to this grea t coopera t ive development en terpr ise, both in this

coun tr y and in England, th ese volumes ar e dedicated.

L. A. DUBRIDGW.



Preface

THIS volume of the Radia t ion Labora tory Ser ies a t tempts to cover

t he basic pr inciples under lying t he opera t ion of klyst rons and planar

gr id tubes as oscilla tors and amplifiers. It has been the desire of the

authors to present the technical and theoret ica l aspects of th is field as

completely and as r igorously as possible, even though this meant the

exclusion of a grea t deal of descr ipt ive mater ia l, and has cer ta inly added

to the difficulty of a fir st reading. Never theless it was felt tha t the

grea test need for a book on this subject a t the present t ime was for one

from which t he fundamenta l pr inciples for the design and understanding

of microwave vacuum tubes could be obta ined. NTOat tempt has been

made to descr ibe how a vacuum tube is actually const ructed. Ra ther

the emphasis has been placed on present ing the fundamenta l mater ia l

which the tube designer or tube user must have at his command.

Because the radio-frequency work of the Radia t ion Labora tory was

con cen tr at ed almost en tir ely in t he fr equ en cy region above 3000 Me/see,this book naturally tends to emphasize the opera t ion of tubes in that

region. However the basic pr inciples a re t he same at lower frequencies

a lthough as a genera l rule the elect r ica l and mechanical requirements

become more difficult to a t tain as higher frequencies a re approached.

Cer ta in ly it is the authors’ hope that this is a book on the pr inciples of

oper at ion of par t icu lar t ypes of tu bes, and n ot a t rea tise on t he gen er at ion

of oscilla t ions in a par ticu la r frequ en cy band.

The wart ime development of microwave radar and communicat ionswas based on three impor tant types of amplifier and oscilla tor tubes: the

mult icavity magnet rons, the klyst ron family of tubes, and the planar

gr id tubes (a lso called ligh thouse tubes and disk-seal tubes). The

ext ra or din ar ily r apid en gin eer in g developmen t of t he mult ica vit y magn e-

t ron as a t ransmit t ing tube is cer ta in ly one of the grea t advances of the

war and is discussed elsewhere in the Radia t ion Laboratory Ser ies. The

present volume at tempts t o complet e t he story, and t o cover in par t icular

the development of microwave receiving tubes, local oscilla tor s, and

signal amplifiers. The use of klyst ron and planar gr id tubes as t rans-

mit t ing oscilla tors, and in a few cases t ransmit t ing amplifiers, is not

neglected. But up to the present their greatest use has been in receivers. ‘.

It seems hardly necessa ry to caut ion the reader tha t the fu ture develop-



PREFACE

ment of microwave receiver tubes will hardly be limited to the two types

discussed here. One need only reca ll the announcemen t in J une of this

yea r of the development fir st a t Oxford University and la ter a t the Bell

Telephone Labora tor ies of the t raveling-wave tube, which may well

r evolu tion ize ou r idea of amplifier design .This volume has been writ t en in par ts based on tube types and con-

st ruct ion , a division in form ra ther than in use or purpose. Following

four in trodu ct or y cha pters discussing t ube t ypes and funct ions and basic

elect ron ic and circu it phenomena common to all types of tubes there is a

pa r t on planar gr id tubes and a par t on klyst rons. This division has

seemed desirable to the authors since it has made the purely mathe-

mat ica l developmen ts more logica l than would have been the case if the

division in funct ion h ad been followed. This a rr an gemen t sh ou ld r edu cethe number of cross references, and make the reading more st ra igh t -

forward. Aside from a few specia l cases of r -f circuit s which are used

solely for microwave vacuum tubes, no a t t empt has been made in this

book to discuss the genera l proper t ies of dist r ibu ted constan t circu it s,

since these problems have been discussed thorough ly elsewhere in this

series.

Except for the impor tan t work of H. V. Neher and his group, most

of the effor t a t Radia t ion Labora tory on microwave receiver s wen t in tothe design of circu its, and the corolla ry tube test ing and specifica t ion .

We have drawn freely upon the work of other organiza t ions both in

England and in th is count ry, and in par t icu lar upon the work of the

BeU Telephone Labora tor ies, the Genera l E lect r ic Company, and the

Sper r y Gyros cope Company. Since the bulk of the war t ime work has

just been declassified and remains unpublished, it has been necessary

t o r efer t o in ter na l or ga niza tion r epor ts, wh ich a re n ot a va ila ble gen er ally.

Wkh the increasing awareness of engineers and physicist s of therela t ive mer it s of var ious systems of units, it has become the du ty of the

preface wr it er t o ment ion and defend the system chosen for the book a t

hand. The present volume uses the MKS system for reasons no more

cogen t than (1) th is system is becoming more and more popula r among

engineers, and is making headway even among physicists; (2) amperes,

ohms, and volt s a re units which the tube designer natura lly uses.

We should like to express our thanks to P rofessor Eugene Feenberg,

now at Washington University in St . Louis, Mr . Edward Bar low, andDr . Marvin Chodorow, of the Sper ry Gyroscope Company for many

helpfu l comments and cr it icism of the manuscr ipt . We are indebted

to our former colleagues Dr . Milton Gardner , now at the University

of Californ ia , and Mr. M. C. Waltz, now at the Bell Telephone Lab-

ora tor ies, for a grea t dea l of help in prepar ing the informat ion for



PREFACE

this volume. In par t icular we wish to thank Dr . W. G. Shepherd, of

t he Bell Teleph on e I,a bor at or ies, who has read the en t ire manuscr ipt

and has helped us grea t ly by his cr it icism.

ALBERT G, HILL.CAMBRIDGEASS.,

J uly, 1946.



Contents

FOREWORDBYL. A. DUBRIDGE . . . . . . . . . v

PREFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. vii

PART I. FUNDAMENTALS

CHAP. 1.

11.

12.

1.3.

14.

15.

16.

CHAP. 2.

2.1.

2.2.2.3.

2.4.

CHAP. 3.

3.1.

3.2.

3.3.

3.4.

3.5.

36.

CHAP. 4.

41.

4.2.

43.

CHAP 5.

5.1.

52 .

53 .

5.4.

5.5.

56 .

5.7.

INTRODUCTION . . . . . . . . . . . . . . . . . . . ...3

Elect ron Tubesa t Very High Frequencies. . . . . . . . 3MicrowaveRegion , . . . . . . . . . . . . . . . . . . . ...4

MicrowaveTechniques. . . . . . ., . . . . . . . . . . ...7

Pr incipa lTube Types . . . . . . . . . . . . . . . . 9

Poin t s of Compar isonbetweenLow-power iVficrowaveTubes . . . 13

Planof th is Book . . . . . . . . . . . . . . . . . . . . ...15

DISCUSSION OF TUBE TYPES AND FUNCTIONS . . . . . . 17

Mixers . . . . . . . . . . . . . . . . . . . . . . . . . ...17

Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . ...18Frequency Mult ipliers .,... . . . . . . . 23

Oscillators . . . . . . . . . . . . . . . . . . . . . . . . ...25

BASIC ELECTRONIC PHENOMENA AT HIGH FREQUENCIES 31

Phenomena of Par t icular Impor tance at High Frequencies. 32

Cur ren t Induced by a Moving Charge 37

Modulat ion of t he Beam..., . . . . . . . . . . . . . . . .39

Genera l Rela t ions in a N’arrow Gap 47

High-velocity Gap . . . . . . . . . ., ., . . . . . . . ...54

Low-velocity Gap, Neglect ing Velocity Spread. 6(3

BASIC CIRCUIT PHENOMIX.4 AT HIGH FREQUENCIES . 70

Cavity Resonators . . . . . . . . . . . . . . . . . . . . . ..7o

Resonator Fields in Pr incipal h~ode ., . . . . 83

Cavity Excita t ion in Principal }Iode. . . 90

PART II. PLANAR 8PACE-CFIAfiGE TUBES

THEORY OF H-F SPACE-CHARGE DEVICES . . . 97

Characterist ics of a Single Region . . . 99

Genera l Relat ions for Mult igr id Tubes . 106

Posit ive-gr id Space-charge-limited Input with }Iinimum near Cathode 110

Gr id-screen and Output Regions, Neglect ing Velocity Spread 115

Posit ive-gr id High-mu Triode with Minimum near Cathode 116

Posit ive-gr id Tet rode with Nfinimum near Cathode. 119

Genera l Relat ions for Velocity-dist r ibut ion Phenomena. 122



CONTENTS

5.8.

5,9.

CHAP. 6.

6.1.62.

6.3.

6.4.

65.

66.

CHAP . 7.

71.

72.

73.

7.4.

75.

76.

7.7.

CHAP . 8.

81 .

8.2.

83 .

84 .

8.5.

86 .

8.7.

Low-velocity Gap without Reflect ions . . 128

Retarding Field with Reflect ions. 138

SPACE-CHARGE DEVICES AS MICROWAVE AMPLIFIERS 146

Int roduct ion . . . . . . . . . . . . .,.......,....146

Elementary Discussion of Gr id-separa t ion Amplifier s 146

Exper imenta l Amplifier Tubes for the 3000-Mc/sec Region 153

N’oise in Microwave .4mplifiers. 157

High-efficiency Amplifiers. 162

Pract ica l Tr iode Amplifiers 163

M1CROW,4VE TRIODE OSCILL.\ TORS. 170

Int roduct ion . . . . . . . .170

Principal Types of Oscillator Circuit s Applicable to Triodes 171

Power Supply and Bias Considera t ions 175

Two-cavity Grid-separat ion Oscillator s 177

Reentran t Oscillators. 179

Behavior of Pract ica l Reent ran t Oscilla tors 183

Modula t ion of Tr iode Oscillator s. 185

PULSE OPERATION OF MICROWAVE TRIODES. 187

Factors Important in Pulse Opera t ion 187

Typical Cavity Design ,. 188

Tube-design Requirements 191

Effect of Pla te-plunger Posit ion 192

Gr id Bias. , . .,, ...,... . . . . . . . . . . . ...193.

Plate and Heater Voltages. . . . . . . . . ...195

Load Coupling . . . . . . . . . . . . .,........,..197

PART III. KLYSTRONS

CHAP . 9. VELOCITY MODULATION AND KLYSTRON BU~CHING 201

91. In t r od u c t ion . . . . . . . . . 201

9.2. Sim p le Ve loc it y Mod u la t ion a n d Bu n ch in g 202

93. Debu n ch in g in a Klys t r on . .209

9.4. Bu n ch in g w it h Fkite Gap-voltage and Arbit ra ry Dr ift -space Charac-

ter ist ics . . . . . . . . . . . .. 218

95. Influence of Finite Gap-transit Angle on Bunching. 224

9.6. Bunching by a Gap Voltage Comparable to Beam Voltage 232

9.7. Analyt ica l Discussion of Bunching by Gap Voltage Comparable to

Beam Voltage . . . . . . . . . . . . . . . . . . . . . ...235

9+LCaecadeBu nching . . . . . . . . . . . . . . . . . . . . .240

9,9. Bunching in the Presence of Harmonic Phase and Amplitude Modula-

t ion . . . . . . . . . . . . . . . . . . . . . . . . . . ...245

CHAP. 10. AMPLIFIER KLYSTRONS. 248

10.1. Mult iresonator Klyst ron Types 248

10.2. General Voltage-amplifier Relat ions 249

10.3. Two-resonator Voltage Amplifiers; Gain. 252

10.4. Voltage-amplifier Klyst rons; Noise. 257



CONTENTS

10.7. Compar ison of Theory and Exper iment for Two-resona tor Amplifier

Klyst rons . . . . . . . . . . . . ., . . . . . . . . ...267

10.8. Voltage Cascade-amplifier Klyst rons 271

10.9. Voltage Cascade Amplifier Gain; Compar ison with Exper iment 278

10,10. Power C4scade-amplifier Klyst rons. 280

CHAP. 11. FREQUENCY MULTIPLIER KLYSTRONS AND TWO-RESON-

ATOR KLYSTRON OSCILLATORS 285

11.1. Frequency Mult iplier Klyst rons 285

11.2. F requency Mult iplier Klyst rons; Compar ison of Theory and Exper i-

mer it . . . . . . . . . . . . . ...290

11,3. Two-resona tor Klyst ron Oscilla tor s. 294

114. Condit ion for Oscilla t ion 297

11.5. Transadmit tance Diagrams 302

11.6. Genera l Oscilla tor Character ist ics . 304

CHAP. 12. REFLEX KLYSTRON OSCILLATORS 31 I

121. Oscilla tor Genera l Behavior . 311

122. Oscilla tor Theory for H igh Modes 317

12.3. Observed Character ist ics of the Reflex Klyst ron 329

12.4. Quan tita t ive Compar ison of Theory and Exper iment . 332

12.5. Deta iled Theory of Idea lized Oscilla tor . 337

CHAP. 13. NONIDEAL REFLECTORS 352

131. D-cElect ronO pt ics . . . . . . . . . . . . . . . . . . . .352

13.2, Genera l Sca iing oi Voltages and Dimensions, 354

133. Reflector Mode Pat terns 357

134. Reflector Mode Pat terns of V,-vs.-x 362

135. h ’ormalized Mode Locus of a Space-charge-free Recessed Reflector . 364

136. Space-charge Transit -t ime Effects in the Plane-para llel Reflector 367

13.7. In fluence of Reflector Field on Bunch ing 373

13,8. D-c Transit T]me vs. Effect ive Bunch ing Time 375

13.9. Bunch ing and Space Charge. 38o

1310. Reflector Fields with Phase Aber ra t ions. 382

13.11. Compar ison of Phase Aber ra t ions and Reflector Nordinear it ies. 382

CHAP . 14. HYSTERESIS IN REFLEX KLYSTRONS. 384

14.1. P h en om en on of Hys t e r e s is 384

14.2. Mod e Asym m e t r y P r od u ced b y Dep en d en ce of G. on @ in Low Modes 385

14.3. Hysteresis Caused by Phase Shift s Dependent upon R-f Gap Voltage

and Independen t of+ O.. . . . ...387

14.4. Bunch ing Theory for Mult iple-t ransit E lect rons 393

14,5. P roduct ion of Hysteresis by Mult iple-t ransit E lect r ons 397

CHAP . 15. LOAD EFFECTS IN REFLEX KLYSTRONS . . 404

15,1. In t r od u ct ion . . . . . . . . . . . . . . . . .,. .4o4

15.2. Ba s is of t h e Cold Te s t ..... . . .405

15.3. Cold Tes t P r oced u r e .,. . . . . . ..4o9

15.4. Ac t ive Op er a t ion ; t h e Id ea l R lek e Dia gr am . . . . . 414

15.5. Tr a n sfor m a t ion h t h e P r a c t ica l R1ek e Dia gr am . . 421

15.6. Exp er im en t a l R iek e Dia gr am s . 432

15.7. E ffect a ofa H igh -Q Lm a d . . . ,, .,............,435



CONTENTS

CHAP . 16. REFLEX-KLYSTRON IvIODULAT’1ON . 441

16.1. Types of Modula t ion . . . . . ...441

16.2. Stat ic Character ist ics Relevant to Low-frequency Modula t ion . 442

16.3. Limita t ions on the Use of Stat ic Character ist ics; the Quasista t ic

Approximat ion in Modula t ion Theory . 444

16.4. Descr ipt ion of Modula t ion; the Small-signal Approximat ion . 446

16.5. Bunch ing in the Presence of Gap-voltage Modulat ion or Transients. 449

166. Effect of Pr imary Modula t ion of Oscilla tor Parameters. 452

16.7. Dr iving of a Resonant Circu it hy a S1OW1YChanging R-f Cur ren t 455

168. Transient Phenomena; Pulse Buildup. 458

16.9. General Oscilla tor Rela t ions with Sinusoida l Modula t ion 462

16.10. Low-frequency Modula t ion of Beam Current and Reflect ion Transit

Time. . . . . . . . . . . . . . . . . . . . . . . . ...465

16.11. Modula t ion of 6’, and 00 at Frequenc ies comparable to @ 469

CHAP . 17. NOISE IN REFLEX KLYSTRONS 47o

17.1. Im p or t a n ce of Oscilla t or Noise . 470

17,2. &fe t h od of Mea su r em en t . . . .471

173. Tot a l Oscilla t o r Noise . . .473

174. Sep a r a t ion of S id eb a n d s . 475

17.5. Dep en d en ce of Noise on Loa d . 477

17.6. Su m m a r y of Noise Beh a vior a n d E s t im a t e of Noise .Ma gn it u d e 479

177. Discu ss ion of Com p lica t in g E ffec t s . 482

1743. Su m m a r y of Resu lt s o f Noise Ca lcu la t ion . 484

17.9. Th eor y of Noise in R eflex Klyst r on . . 489

CHAP. 18. PRACTICAL REFLEX KLYSTRONS . 495

18.1. In t roduct ion . . . . . . . . . . . . . . . . . . . .. 495

18.2. Resona tor Design in Rela t ion to Per formance 49S

183. TuningMethods . . . . . . . . . . . . . . . . . . . . . . ..502

18.4. Output Couplings . . . . . . . . . . . . . . . . .507

18.5. Descr ipt ion of Some Representat ive Reflex Tubes . . 508

18.6. Power Supplies . . . . . . . . . . . . . . . . . . . . . . ..521

INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..527

mit radiaton lab series, v7, klystrons and microwave triodes - front matter, preface, contents

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