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power gain can be created in one or more specific

directions by reducing power in other directions.

The result is often called a uni-directional signal

(Figure

G

). These are described as beam or

directional antennas and are either fixed at

a specific target to improve transmission and

reception or rotated to change targets (Figure

H

).

EM waves’ ability to reflect can be leveraged to

great effect when they are aimed at a parabolic

dish. Satellite dishes and space telescopes both

use the same principle of concentrating a tight

capture area into a small point for reception

and focusing the output of a small point into a

directional beam for transmission. ...