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Re: About wireless energy transfer
Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>
At 07:49 PM 2/9/2007, Tesla list wrote:
Original poster: Ed Phillips <evp@xxxxxxxxxxx>
I'm not disputing the case for low efficiency, for a single
device, but what if there were, say, 20 or 30 of those devices
within the field?"
If there were the transfer to each one would have an efficiency
determined by its unique coupling to the "transmitter". If they
were separated from each other by enough that there was no mutual
coupling between them [the receivers] then the total power would be
the sum of the individual powers.
Having spent the better part of the last 5 years working on research
into novel ways to do non-microwave phased arrays, the statement:
"separated by enough so there's no mutual coupling" says it all...
That's the rub. At distances <1 wavelength there will always be
mutual coupling to deal with..except for some "special cases" like
two coils that are orthogonal.
Yes, one can come up with schemes to adjust everything to compensate
for the mutual coupling, but that requires knowing what the couplings
are (non trivial), a way to do the adjusting (non-trivial), and a way
to do the calculations (non-trivial). All of these also require some
non-zero amount of power to do.