Thread: Superposition
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Old November 17th 07, 05:49 PM posted to rec.radio.amateur.antenna
Richard Fry Richard Fry is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 440
Default Superposition

"K7ITM" wrote
Assuming the two "waves" existed independently at some points
in space, you'll have to first tell us _exactly_ what was done to
combine them into one wave.

__________

The physics of EM radiation.

As an example, consider an array comprised of two, identical radiators on
the same vertical axis, in the same physical orientation, with a vertical
separation of 1 wavelength, each driven with equal r-f power and relative
phase by the same r-f source.

The fields from the two radiators are generated and radiated separately, but
once well past the near-field boundary of the array, the EM field existing
at every point in free space will be the vector sum of those separate
fields.

When the net field at the radiation peak of the array is measured in the far
field, there will be no way to determine from that measurement whether the
field was generated using a single radiator with X power input, or the
described 2-element array having about 1/2 that power input.

RF