Microwave and Millimeter-Wave Vacuum Electron Devices: Inductive Output Tubes, Klystrons, Traveling-Wave Tubes, Magnetrons, Crossed-Field Amplifiers, and Gyrotrons

Microwave and Millimeter-Wave
Vacuum Electron Devices Inductive Output Tubes, Klystrons,Traveling-Wave Tubes, Magnetrons,Crossed-Field Amplifiers, and Gyrotrons
Contents
Preface
Chapter 1
Introduction
1.1 THE DOMAIN OF RF VACUUM ELECTRON DEVICES
1.2 CLASSIFICATION OF RF VACUUM ELECTRON DEVICES
1.2.1 Inductive Output Tubes
1.2.2 Linear Beam Devices
1.2.3 Crossed-Field Devices
1.2.4 Gyro-Devices
1.3 CAPABILITIES OF RF DEVICES
1.4 OVERVIEW OF THIS BOOK
REFERENCE
Chapter 2 Basic Properties of Electromagnetic Waves
2.1 WAVE PROPAGATION
2.2 GROUP AND PHASE VELOCITY
2.3 DISPERSION
2.3.1 Coaxial Line
2.3.2 Rectangular Waveguide
2.4 MODES
2.4.1 Modes in Rectangular Waveguide
2.4.2 Modes in a Circular Waveguide
2.5 PERIODICALLY LOADED WAVEGUIDE
2.6 EFFECT OF SKIN DEPTH
REFERENCE
Chapter 3
Vacuum Requirement
3.1 VACUUM LEVEL
3.1.1 Gas Density
3.1.2 Monolayer Formation Time
3.1.3 Viscous and Molecular Flow
3.1.4 Bakeout
3.1.5 Materials Selection
Chapter 4
Thermionic Cathodes
4.1 THERMIONIC EMISSION
4.1 Thermionic Emission
4.1.1 Schottky Effect
4.1.2 Space-Charge Limitation
4.2 EVOLUTION OF THERMIONIC CATHODES
4.3 DISPENSER CATHODES
4.3.1 Fabrication
4.3.2 Controlled Porosity Reservoir Cathodes
4.3.3 Operation of Dispenser Cathodes
4.3.4 Miram Curves
4.3.5 Work Function Distribution
4.4 SCANDATE CATHODES
4.4.1 Background
4.4.2 Structure and Fabrication
4.4.3 Operation
4.4.4 Electron Cooling
4.4.5 Emission Uniformity
4.4.6 Scandate-Cathode Life
4.4.7 Robustness
4.4.8 Anomalous Behavior
4.5 LIFE CONSIDERATIONS
4.5.1 Grant and Falce Life Prediction Model
4.5.2 Longo Life Prediction Model
4.6 DISPENSER CATHODE SURFACE PHYSICS
4.7 HEATERS
4.7.1 Conventional Heater Assemblies
4.7.2 Fast Warm-Up Heaters
4.7.3 Heater Testing
4.7.4 Effect of Filament Magnetic Field
REFERENCES
Chapter 5 Cold Cathodes
5.1 SECONDARY EMISSION CATHODES
5.1.1 Introduction
5.1.2 Characteristics of Secondary Emission
5.1.3 Energy of Impacting Primary Electrons
5.1.4 Angle of Incidence of Primary Electrons
5.1.5 Secondary Emitting Properties of Surfaces
5.1.6 Energy Distribution of Secondary Electrons
5.1.7 Modeling of Secondary Emission Characteristics
5.1.8 Operation of Cathodes in Crossed-Field Devices
5.2 FIELD EMISSION CATHODES
5.2.1 Field Emission
5.2.2 Cathode Assembly
5.2.3 Proof of Principle Tests
5.2.4 Cathode Failure Mechanisms and Failure Prevention
REFERENCES
Chapter 6 Electron Guns for Linear-Beam Tubes
6.1 PIERCE GUNS
6.1.1 Focus Electrodes for Parallel Flow
6.1.2 Focus Electrodes for Convergent Flow
6.1.3 Defocusing Effect of Anode Aperture
6.1.4 Formation of Minimum Beam Diameter
6.1.5 Thermal Velocity Effects
6.1.6 Effects of Patchy Emission and Cathode Roughness
6.2 BEAM CONTROL TECHNIQUES
6.2.1 Cathode Pulsing
6.2.2 Modulating Anode
6.2.3 Control Focus Electrodes
6.2.4 Grids
6.2.5 Summary of Beam Control Electrode Characteristics
REFERENCES
Chapter 7
Electron Beams from Pierce Guns
7.1 UNIFORM-FIELD FOCUSING AND LAMINAR FLOW
7.1.1 Brillouin Flow
7.1.2 Scalloping
7.1.3 Confined (Immersed) Flow
7.2 UNIFORM-FIELD FOCUSING AND NONLAMINAR FLOW
7.3 FOCUSING WITH PERMANENT MAGNETS
7.3.1 Overview
7.3.2 Laminar Flow, No Cathode Flux
7.3.3 Laminar Flow with Cathode Flux
7.3.4 Nonlaminar Flow
REFERENCES
Chapter 8
Beam Modulation in Linear Beam Tubes
8.1 BEAM MODULATION
8.1.1 Density Modulation
8.1.2 Velocity Modulation
8.1.3 Gridded (Planar) Gaps
8.1.4 Gridless (Nonplanar) Gaps
8.2 BEAM LOADING
8.3 BUNCHING
8.3.1 Ballistic Bunching
8.3.2 Bunching with Space-Charge Forces
8.4 TRANSITION TO LARGE SIGNAL BUNCHING
8.4.1 Bunching with and without Space-Charge Effects
8.4.2 Mihran’s Experimental Results
8.4.3 Webber’s Disk and Ring Model Results
REFERENCES
Chapter 9 Current Induction and Circuit ResponseIn
9.1 CURRENT INDUCTION
9.1.1 Ramo’s Theorem
9.1.2 Induced Current Waveform
9.1.3 RF Current Induced by an Electron Beam
9.2 CIRCUIT RESPONSE
9.2.1 Parallel RLC Circuit
9.2.2 Resistive Load
9.2.3 Inductive Load
9.2.4 Capacitive Load
9.2.5 Total Cavity Response
REFERENCE
Chapter 10
Inductive Output Tubes
10.1 INTRODUCTION
10.2 HISTORY AND BASIC OPERATION OF THE IOT
10.3 ELECTRON GUN
10.3.1 Grid
10.3.2 Density Modulation
10.3.3 Transit Time, Frequency Limit
10.3.4 Linearity
10.3.5 Efficiency
10.4 OUTPUT CIRCUIT
10.4.1 Bandwidth
10.5 COLLECTOR
10.6 POWER
10.7 SIZE AND WEIGHT
10.8 APPLICATIONS
10.8.1 IOTs for Television
10.8.2 Single-Beam IOTs for Accelerators
10.8.3 Multiple-Beam IOTs for Accelerators
REFERENCES
Chapter 11 Basic Klystrons and Their Operation
11.1 INVENTION OF THE KLYSTRON
11.1.1 Reflex Klystrons
11.2 BASIC OPERATION OF A KLYSTRON
11.2.1 Cavity Operation
11.2.2 Coupling to a Cavity
11.2.3 Tuners and Tuning
11.3 KLYSTRON DRIVER SECTIONS
11.3.1 Gain and Bandwidth
11.4 KLYSTRON OUTPUT SECTION
REFERENCES
Chapter 12
Klystron Performance
12.1 LEGACY KLYSTRONS
12.2 POWER
12.2.1 Pulsed Operation
12.2.2 Limits on Beam Voltage
12.2.3 Limits on Beam Current
12.2.4 Estimate of Obtainable Power
12.2.5 CW Operation
12.3 BANDWIDTH
12.3.1 Driver Section
12.3.2 Output Sections
12.4 EFFICIENCY
12.4.1 Background
12.4.2 The Need for Extremely High Efficiency
12.4.3 COM and BAC Tuning
12.5 MULTIPLE BEAM KLYSTRONS
12.5.1 Background
12.5.2 Fundamental Mode Resonators
12.5.3 Higher-Order Mode Resonators
12.6 MILLIMETER-WAVE EXTENDED-INTERACTION KLYSTRONS
12.6.1 EIK Components
12.6.2 EIK Operation
12.6.3 Applications
REFERENCES
Chapter 13 Traveling-Wave Interaction
13.1 INVENTION OF THE HELIX TWT
13.1.1 Haeff
13.1.2 Lindenblad
13.1.3 Kompfner
13.2 BASIC OPERATION OF THE HELIX TWT
13.2.1 The Helix
13.2.2 Space-Charge Waves
13.2.3 Plasma Frequency Reduction Factor
13.2.4 Experimental Verification
13.3 TWT GAIN
13.3.1 Effect of Loss
13.3.2 Effect of Space Charge
3.4 SATURATION
13.4.1 Discussion of Interactions
13.4.2 Estimates of Maximum Efficiency
REFERENCES
Chapter 14
Helix TWT Performance
14.1 BANDWIDTH
14.1.1 Dispersion
14.1.2 Dispersion Control
14.2 GAIN
14.2.1 Transitions
14.2.2 Attenuators and Severs
14.3 POWER
14.3.1 Peak Power
14.3.2 Average Power
14.3.3 Repetition Rate Limitations
14.4 EFFICIENCY
14.5 SATELLITE COMMUNICATIONS
14.6 DUAL-MODE OPERATION
14.7 MICROWAVE POWER MODULES
14.8 RING-BAR and RING-LOOP TWTS
REFERENCES
Chapter 15
Coupled-Cavity TWTs
15.1 BASIC OPERATING PRINCIPLES
15.1.1 Beam-Circuit Interaction
15.1.2 Cavity-to-Cavity Coupling
15.2 FUNDAMENTAL BACKWARD-WAVE OPERATION
15.2.1 Dual Inline Slot
15.2.2 Staggered Slot
15.2.3 Millimeter-Wave Construction Techniques
15.2.4 Dual-Staggered Slot
15.3 FUNDAMENTAL FORWARD-WAVE OPERATION
15.4 TWYSTRONS
15.5 CURNOW-GITTINS EQUIVALENT CIRCUIT
REFERENCES
Chapter 16
Collectors for Linear-Beam Tubes
16.1 POWER DISSIPATION
16.2 POWER RECOVERY
16.2.1 Power Flow
16.2.2 Power Recovery with a Depressed Collector
16.2.3 Electron Energy Distribution
16.2.4 Spent Beam Power
16.2.5 Effect of Body Current
16.2.6 Multistage Depressed Collectors
16.2.7 Individual Lens Collectors
16.2.8 Operation at Reduced Drive Levels
16.2.9 Efficiency vs. Number of Depressed Stages
16.2.10 Secondary Electrons in Depressed Collectors
16.2.11 Power Supply Considerations
16.3 COLLECTOR COOLING
16.3.1 Conduction Cooling
16.3.2 Convection Cooling
16.3.3 Forced-Air Cooling
16.3.4 Forced-Flow Liquid Cooling
16.3.5 Vapor Phase Cooling
16.3.6 Radiation Cooling
REFERENCES
Chapter 17 Distortion in Linear-Beam Tubes
17.1 DISTORTION RESULTING FROM SATURATION EFFECTS
17.1.1 AM/AM Conversion
17.1.2 AM/PM Conversion
17.1.3 Harmonic Generation
17.1.4 Intermodulation Products
17.2 DIGITAL COMMUNICATIONS
17.2.1 QPSK and 16QAM
17.2.2 Data Characteristics
17.2.3 Amplifier Design to Reduce Distortion
17.3 SIGNAL CAPTURING
17.4 VARIATIONS WITH FREQUENCY
17.4.1 Broadband Gain Variations
17.4.2 Narrowband Gain Variations
17.4.3 Phase Nonlinearities or Time-Delay Distortion
17.5 PUSHING AND PULLING
17.5.1 Amplitude Pushing
17.5.2 Phase Pushing
17.5.3 Pulling
REFERENCES
Chapter 18
Noise in Linear-Beam Tubes
18.1 THERMAL AGITATION NOISE
18.2 DEFINITIONS OF NOISE FIGURE
18.3 OVERVIEW OF NOISE PHENOMENA
18.4 NOISE IN ELECTRON GUNS
18.5 NOISE GENERATION AT THE CATHODE
18.5.1 Shot Noise
18.5.2 Velocity Noise
18.5.3 Other Noise Generation Mechanisms
18.6 THE SPACE-CHARGE MINIMUM REGION
18.6.1 Rack Noise Invariance
18.6.2 Shot Noise Reduction
18.6.3 Other Noise Effects
18.6.4 Noise Space-Charge Waves
18.7 RF SECTION NOISE PHENOMENA
18.7.1 Impedance Transformation
18.7.2 Lens Effects
18.7.3 Circuit Loss
18.7.4 Partition Noise
18.7.5 Secondary Electron InteractionsThe electron beam striking the collector generates
18.8 OTHER NOISE SOURCES
REFERENCES
Chapter 19
Magnetrons
19.1 ELECTRON FLOW WITH NO RF FIELDS
19.2 TYPES OF MAGNETRONS
19.2.1 Cyclotron-Frequency Magnetrons
19.2.3 Traveling-Wave Magnetrons
19.3 OPERATION OF THE TRAVELING-WAVE MAGNETRON
19.3.1 Hub Formation
19.3.2 The Hartree Voltage
19.3.3 Spoke Formation
19.3.4 Conversion of Potential Energy to RF Energy
19.3.5 RF Circuit Operation
19.4 MODING
19.5 COAXIAL MAGNETRONS
19.6 INVERTED MAGNETRONS
19.7 MAGNETRON TUNING
19.8 OUTPUT COUPLERS AND TRANSFORMERS
19.9 CATHODE AND HEATER OPERATION
19.10 PERFORMANCE
19.10.1 Voltage-Current Characteristics
19.10.2 Frequency Pushing
19.10.3 Frequency Pulling
19.10.4 Thermal Drift
19.11 APPLICATIONS OF MAGNETRONS
19.11.1 Conventional Magnetrons
19.11.2 Frequency-Agile Magnetrons
19.11.3 Signal Injected Magnetrons
19.11.4 Beacon Magnetrons
19.11.5 Microwave Oven Magnetrons
19.11.6 Industrial Heating Magnetrons
19.11.7 Low-Noise Magnetrons
19.11.8 Magnetrons for Power Beaming
19.11.9 Relativistic Magnetrons
19.12 SUMMARY OF POWER CAPABILITIES
REFERENCES
Chapter 20
Crossed-Field Amplifiers
20.1 INTRODUCTION
20.1.1 Injected-Beam CFAs
20.1.2 Distributed Emission CFAs
20.2 CFA OPERATION
20.2.1 Electron Emission and Hub Formation
20.2.2 Spoke Formation and Growth
20.3 CFA SLOW-WAVE CIRCUITS
20.4 CFA PERFORMANCE
20.4.1 Forward-Wave CFAs
20.4.2 Backward-Wave CFAs
20.4.3 DC Operation
20.4.4 Gain and Operating Limits
20.4.5 CFA Phase Characteristics
20.4.6 Weight and Size Considerations
20.5 POWER CAPABILITIES
20.6 THERMAL CONSIDERATIONS
20.7 CFA POWER SUPPLY CONSIDERATIONS
20.7.1 DC-Operated Supplies
20.7.2 Cathode-Pulsing Supplies
REFERENCES
Chapter 21
Gyrotrons
21.1 INTRODUCTION
21.2 BASIC INTERACTION MECHANISM
21.3 MAGNETRON INJECTION GUNS
21.3.1 MIG Configurations
21.3.2 First-Order Design
21.3.3 MIG Performance
21.4 BEAM-WAVE INTERACTION
21.4.1 Cavities
21.4.2 Harmonic Operation
21.5 GYRO-AMPLIFIERS
21.5.1 Gyro-Klystrons
21.5.2 Gyro-TWTs
21.5.3 Gyro-Twystrons
21.6 MEGAWATT-CLASS GYROTRONS
21.6.1 Applications for MW Gyrotrons
21.6.2 The Year of the Gyrotron
21.7 ENABLING TECHNOLOGIES FOR MEGAWATT GYROTRONS
21.7.1 Mode Converters
21.7.2 Coaxial MIGs
21.7.3 Coaxial Cavities
21.7.4 Step Frequency Tuning
21.7.5 Collectors
REFERENCES
Chapter 22
Windows
22.1 BACKGROUND
22.2 COAXIAL WINDOWS
22.3 CONVENTIONAL WAVEGUIDE WINDOWS
22.4 MEGAWATT AVERAGE POWER WINDOWS
22.4.1 Step Tuning
22.5 SCALING OF WINDOWS
REFERENCES
Appendix A
Useful Constants and Conversions
Appendix B Vacuum Technology
B.1 UNITS OF MEASUREMENT
B.2 RANGES OF OPERATION
B.3 SOURCES OF GAS
B.3.1 Backstreaming
B.3.2 Permeation
B.3.3 Diffusion
B.3.4 Desorption
B.3.5 Vaporization
B.3.6 Virtual Leaks
B.3.7 Real Leaks
B.4 VACUUM SYSTEMS
B.5 ROUGHING PUMPS
B.5.1 Oil-Filled Mechanical Pumps
B.5.2 Scroll Pumps
B.5.3 Sorption Pumps
B.5.4 Venturi Pumps
B.6 HIGH-VACUUM PUMPS
B.6.1 Diffusion Pumps
B.6.2 Ion Pumps
B.6.3 Turbomolecular Pumps
B.6.4 Cryogenic Pumps
B.6.5 Nonevaporable Getters
B.7 VACUUM GAUGES
B.7.1 Thermocouple Gauge
B.7.2 Ionization Gauge
B.8 BAKEOUT
B.9 MICROWAVE TUBE MATERIALS
B.10 JOINING TECHNIQUES
B.10.1 Brazing
B.10.2 Welding
REFERENCES
Appendix C
Magnetics
C.1 MAGNETIC QUANTITIES
C.2 MAGNETIC CIRCUITS
C.3 MAGNETIC MATERIALS
C.3.1 Ferromagnetic Materials
C.3.2 Normal and Intrinsic Hysteresis Curves
C.3.3 Energy Product
C.3.4 Rare Earth Magnet Materials
C.4 PERMANENT MAGNETS
C.4.1 Straight-Field Magnets
C.4.2 Periodic Permanent Magnets
C.4.3 Double-Period and Long-Period Focusing
C.5 POLE PIECES
C.6 ELECTROMAGNETS
REFERENCES
Appendix D
Cyclotron, Larmor, and Scallop Frequencies
D.1 CYCLOTRON FREQUENCY
D.2 BUSCH’S THEOREM
D.3 LARMOR FREQUENCY
D.4 SCALLOP FREQUENCY
Appendix E
Breakdown and Protection
E.1 FIELD ENHANCEMENT
E.2 DC BREAKDOWN IN VACUUM
E.2.1 Electrode Phenomena Leading to Breakdown
E.2.2 Avoiding Breakdown
E.2.3 Vacuum Arcs
E.3 DC BREAKDOWN ON INSULATOR SURFACES
E.4 RF BREAKDOWN IN VACUUM
E.4.1 Two-Surface Multipactor with No Magnetic Field
E.4.2 Two-Surface Multipactor in Combined Fields
E.4.3 Single-Surface Multipactor with No Magnetic Field
E.4.4 Single-Surface Multipactor in Combined Fields
E.5 RF BREAKDOWN OF INSULATORS
E.6 DC BREAKDOWN IN GAS
E.7 RF BREAKDOWN IN GAS
E.8 FAULT DETECTION AND TUBE PROTECTION
E.8.1 Excess Body Current
E.8.2 Excess Reflected RF Power
REFERENCES
Glossary
About the Author
Index