O-Type Microwave Devices

Abstract

O-type microwave vacuum electron devices are considered. This type of devices use dynamic control on electron beam. Basic concepts of operation, linear theory of bunching, elements of nonlinear theory are presented. Main representatives of the O-type devices are described, their construction, characteristics and parameters are introduced. The problem of increasing maximum working frequency of these devices is discussed and possible ways of this problem decision are listed. The constant magnetic field in these devices is used only for transporting the beam and does not participate in the interaction process. Klystrons, traveling wave tubes, backward wave oscillators and hybrid devices are among the representatives of this type of device.

Advancement Questions

• 1. Describe the main phases of the energy conversion process in O-type devices.

• 2. List the main parts of the double-cavity drift klystron and describe the principle of its operation.

• 3. What is the average interaction coefficient and how does it depend on the radius of the drift channel and the beam radius?

• 4. What is the grouping parameter? What is the optimal value of this parameter for the amplifier klystron?

• 5. How is the disruption of longitudinal electrons taken into account when analyzing the grouping process?

• 6. What is the electronic efficiency of the klystron and on which device parameters does it depend? What is the maximum value of the electronic efficiency of the double-cavity drift klystron?

• 7. How do you determine the gain of the double-cavity drift klystron?

• 8. What tuning circuits are you aware of for multi-cavity klystrons?

• 9. What determines the electronic efficiency of the multi-cavity klystron?

• 10. What determines the bandwidth of the multi-cavity klystron?

• 11. What methods for the frequency band expansion for the multi-cavity klystron do you know?

• 12. What other types of klystrons are you aware of besides transit-time amplifiers? Describe the principle of their operation.

• 13. Describe the history of the creation, and the operating principle of O-type TWTs.

• 14. Write down the TWT dispersion equation and analyze the dependence of its roots on the tube parameters.

• 15. What determines the gain in the low-signal approximation?

• 16. What determines electronic efficiency of a TWT?

• 17. What methods of increasing TWT efficiency do you know?

• 18. What types of SWS are used in the TWT? What is the difference between the TWT on the helix and the TWT on coupled resonators?

• 19. What are the advantages of hybrid devices?

• 20. Describe the construction and operating principle of the twistron.

• 21. Describe the construction of the klystrode. What are its differences from the klystron?

• 22. Describe the design and operating principle of the orotron.