High Power Microwave Tubes: Volume 1
- Vishal Kesari, B. N. Basu
- January 2018
Description
Our aim in this book is to present a bird's-eye-view of microwave tubes (MWTs) that continue to be important despite competitive incursions from solid-state devices. We have presented a broad and introductory survey that we hope the readers would be encouraged to read rather than going through lengthier books, and subsequently explore the field of MWTs further in selected areas of relevance to their respective interests. We hope that this book will motivate newcomers to pursue research in MWTs, and offer the opportunity for readers an overview of the salient features and prospects, as well as the trends and progress of them. The scope of ever-expanding applications of MWTs in the high-power and high-frequency regime will sustain and intensify the research and development in MWTs in coming years.
Volume 1 of the book describes the historical timeline of the development of MWTs, the high-frequency limitations of traditional electron tubes, means of overcoming them and the factors making MWTs superior to solid-state devices.
About Editors
Vishal Kesari is Scientist at Microwave Tubes Research and Development Centre Defence Research and Development Organisation, Bangalore, India. He has authored two books and numerous research papers in peer-reviewed journals and conference proceedings.
B N Basu received his PhD from Institute of Radiophysics and Electronics, Calcutta University. He served several high-profile organizations in India and visiting assignments in the UK, Korea and Germany. He was President of Vacuum Electron Devices and Application Society, Bengaluru. He has authored or co-authored more than 100 research papers in journals and six monograph chapters in the area of microwave tubes, and has written four books across multiple publishers.
Table of Contents
Volume 1
Page No.
Foreword
i
Preface
ii
Acknowledgement
iv
Chapter 1
Introduction
1-15
Order of vacuum
5
High frequency limitations of electron tubes
6
Tiny electron tubes to alleviate high-frequency limitation
10
Advent of transit-time microwave tubes
11
Solid state devices versus microwave tubes
11
Organization of the book
14
Chapter 2
Microwave Tubes: Classification, Applications and Trends
16-25
2.1
Classification
16
2.2
Applications
18
2.3
Trends in Research and Development
21
Chapter 3
Basic Enabling Concepts
26-47
3.1
Cathode
26
3.2
Space-Charge-Limited and Temperature-Limited Emission
28
Child-Langmuir's relation under space-charge-limited condition of emission
29
Richardson-Dushman's relation under temperature-limited condition of emission
31
3.3
Space-Charge Waves and Cyclotron Waves
31
Space-charge waves
31
Cyclotron waves
33
3.4
Electron Bunching Mechanism
34
3.5
Induced Current due to Electron Beam Flow
38
3.6
Space-Charge-Limiting Current
40
Space-charge limited current for an infinitesimally thin hollow electron beam in a metal envelope
41
Space-charge limited current for a thick solid electron beam in a metal envelope
43
3.7
Conservation of Kinetic Energy in M-Type Tubes
45
Chapter 4
Formation, Confinement and Collection of An Electron Beam
48-72
4.1
Electron Gun
48
Pierce gun derived from a flat cathode
48
Pierce gun derived from a curved cathode
50
Magnetron injection gun for the formation of a gyrating electron beam
60
4.2
Magnetic Focusing Structure
61
Busch's theorem
62
Brillouin focusing
63
Confined-flow focusing
66
Periodic permanent magnet focusing
67
4.3
Multistage Depressed Collector
70
Chapter 5
Analytical Aspects of Beam-Absent and Beam-Present Slow-Wave and Fast-Wave Interaction Structures
73-134
5.1
Analysis of Helical Slow-Wave Interaction Structures
75
5.1.1 Sheath-helix model
76
Field analysis of a helix in free space
76
Equivalent-circuit analysis of a helix in free space
78
Modeling of dielectric helix-supports of wedge cross section
80
Modeling of finite helix thickness
84
Modeling of dielectric helix-supports deviating from wedge cross section
84
Effect of non-uniformity of radial propagation
85
Modeling of vane-loaded metal envelope
86
Effect of structure losses
87
Asymmetry of dielectric helix-support rods
88
5.1.2 Tape-helix model
90
Dispersion relation of a helix in free space in the tape-helix model
90
Dispersion relation of a loaded helix in the tape-helix model
92
5.1.3 Interaction impedance
93
5.1.4 Dispersion and interaction impedance characteristics
94
5.2
Analysis of Fast-Wave Disc-Loaded Waveguide Interaction Structures
100
5.2.1 Steps for obtaining dispersion relation/characteristics
100
5.2.2 Steps for obtaining interaction impedance characteristics
101
5.2.3 Models of axially periodic structure
102
Infinitesimally thin metal disc-loaded circular waveguide
102
Disc-loaded circular waveguide of finite disc-thickness
102
Interwoven-disc-loaded circular waveguide
102
Alternate dielectric and metal disc-loaded circular waveguide
103
5.2.4 Field intensities in structure regions
104
Disc-free region
104
Disc-occupied region
105
Infinitesimally thin metal disc-loaded circular waveguide and disc-loaded circular waveguide of finite disc-thickness
105
Interwoven-disc-loaded circular waveguide
106
Alternate dielectric and metal disc-loaded circular waveguide
106
5.2.5 Relevant boundary conditions
107
5.2.6 Dispersion relation
107
Infinitesimally thin metal disc-loaded circular waveguide
107
Disc-loaded circular waveguide of finite disc-thickness
107
Interwoven-disc-loaded circular waveguide
107
Alternate dielectric and metal disc-loaded circular waveguide
108
5.2.7 Azimuthal interaction impedance
109
5.2.8 Structure characteristics
111
Dispersion characteristics
111
Azimuthal interaction impedance characteristics
122
5.3
Growing-Wave Interactions in Slow-Wave TWTs and Fast-Wave Gyro-TWTs
126
5.3.1 Beam-present dispersion relations
127
5.3.2 Gain-frequency response
129
Dimensional tapering for gyro-TWT broadbanding
131
References
135-138
Bibliographic
Paperback ISBN: 9780750328982
Ebook ISBN: 9781681745626
DOI: 10.1088/978-1-6817-4561-9
Publisher: Morgan & Claypool Publishers