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CHAPTER 3
PRINCIPLES OF TRANSMISSION LINES
LEARNING OBJECTIVES
Upon completion of this chapter, you will be able to:
1. State what a transmission line is and how transmission lines are used.
2. Explain the operating principles of transmission lines.
3. Describe the five types of transmission lines.
4. State the length of a transmission line.
5. Explain the theory of the transmission line.
6. Define the term LUMPED CONSTANTS in relation to a transmission line.
7. Define the term DISTRIBUTED CONSTANTS in relation to a transmission line.
8. Define LEAKAGE CURRENT.
9. Describe how the electromagnetic lines of force around a transmission line are affected by the
distributed constants.
10. Define the term CHARACTERISTIC IMPEDANCE and explain how it affects the transfer of
energy along a transmission line.
11. State how the energy transfer along a transmission line is affected by characteristic impedance and
the infinite line.
12. Identify the cause of and describe the characteristics of reflections on a transmission line.
13. Define the term STANDING WAVES as applied to a transmission line.
14. Describe how standing waves are produced on a transmission line and identify the types of
terminations.
15. Describe the types of standing-wave ratios.
INTRODUCTION TO TRANSMISSION LINES
A TRANSMISSION LINE is a device designed to guide electrical energy from one point to another.
It is used, for example, to transfer the output rf energy of a transmitter to an antenna. This energy will not
travel through normal electrical wire without great losses. Although the antenna can be connected directly
to the transmitter, the antenna is usually located some distance away from the transmitter. On board ship,
