On Wed, 08 Sep 2004 23:56:20 -0700, Roy Lewallen hath writ:
The fact that you can extract only half the power from a wave with a
perfectly efficient antenna is already built into Ae. That is, Ae = P/S,
where P is the power delivered to a conjugate load and S is the power
density of the wave.

I suspect that in your reference, Ea is the *peak*, not RMS, field
strength, and that's why the factor of two.

Incidentally, while you can extract only half the power from a wave with
a perfectly efficient antenna, it is possible to extract *all* the power
from a wave. An anechoic chamber extracts essentially all the power from
waves generated within it.

As well, the universe, in all it's vastness, eventually "...extracts
essentially all the power from waves generated..." by _any_ source. HI!HI!

Jonesy, W3DHJ
--
| Marvin L Jones | jonz | W3DHJ | linux
| Gunnison, Colorado | @ | Jonesy | OS/2 __
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