g. Tracking radar sets have a beam that is narrow both vertically and
horizontally.
20. Reflectors are used with radar antennas to produce correctly shaped
beams.
a. Radar sets operate in the microwave region of the frequency
spectrum. Microwave frequency wavelengths are so small that they act like
light waves.
That's why most sets use antenna reflectors that work like
light reflectors. There are four main types of antennas that you will work
with, as follows:
(1) Paraboloid (dish)
(2) Orange peel.
(3) Parabolic cylinder.
(4) Metallic lens.
b. The first three types of antennas get their names from the shape of
their reflectors. The metallic lens type is actually a lens made of metal.
21. Radar reflectors work like light reflectors.
a. Take a look at a flashlight and notice the reflector surrounding the
bulb.
The reflector concentrates light from the bulb into a narrow beam.
Similarly, a radar reflector concentrates RF energy from the antenna into a
narrow beam as shown in Figure 143.
b. Without a reflector, light from the flashlight bulb would go out in
all directions, and so would RF energy from the antenna.
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