LESSON FOUR
ANTENNAS AND WAVEGUIDES
TASK
Describe how RF energy is transferred through waveguides, recognize the
various waveguide tuning and coupling devices, identify the various antennas
and reflectors used in radar systems, and differentiate between front and
rear antenna feed systems.
CONDITIONS
(Performance-Oriented) Given this subcourse, pencil, and paper.
STANDARD
(Performance-Oriented) Demonstrate competency of task skills and knowledge
by correctly responding to 75 percent of the multiple-choice test covering
radar transmitters.
REFERENCES
TC 11-67
FM 11-63
Learning Event 1:
WAVEGUIDES
1.
General.
All transmission lines have power losses that increase as the
applied frequency rises.
In fact, at microwave frequencies, ordinary RF
transmission lines losses are so great that their use is impractical. As a
result, transmission engineers have devised a new transmission medium for
guiding microwave energy from one place to another. They use waveguides as
the transmission medium.
Waveguides give much lower power losses at
microwave frequencies than you would get using ordinary RF transmission
lines. Figure 105 shows waveguide directing energy to a radar antenna.
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