2-1
CHAPTER 2
MICROWAVE COMPONENTS AND CIRCUITS
LEARNING OBJECTIVES
Upon completion of this chapter the student will be able to:
1. Explain the basic principles of microwave tubes and describe the limitations of conventional
tubes.
2. Describe the basic principles of velocity modulation.
3. Outline the development of microwave tubes.
4. Describe the basic theory of operation of klystrons including multicavity and reflex klystrons.
5. Explain the basic theory of operation of traveling-wave tubes and backward-wave oscillators.
6. Describe the construction, basic theories of operation, and typical applications of magnetrons and
amplitrons.
7. Describe the basic theory of operation of tunnel diodes when used in oscillator-, amplifier-, and
frequency-converter circuits.
8. Explain the operation of varactors when used in parametric amplifiers and frequency converters.
9. State the basic principles of operation of bulk-effect diodes and the gunn oscillator.
10. Explain the basic operation of passive microwave diodes in terms of theory and application.
11. Explain the basic operation of microwave transistors in terms of theory and application.
MICROWAVE COMPONENTS
The waveguides discussed in chapter 1 serve to transport microwave energy from one place to
another. Energy is transported after it has been generated or amplified in a previous stage of the circuit. In
this chapter you will be introduced to the special components used in those circuits.
Microwave energy is used in both radar and communications applications. The fact that the
frequencies are very high and the wavelengths very short presents special problems in circuit design.
Components that were previously satisfactory for signal generation and amplification use are no longer
useful in the microwave region. The theory of operation for these components is discussed in this chapter.
Because the theory of operation is sometimes difficult to understand, you need to pay particular attention
to detail as you study this chapter. It is written in the simplest manner possible while retaining the
necessary technical complexity.
