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Re: About wireless energy transfer



Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 08:03 PM 2/9/2007, Tesla list wrote:
Original poster: Ed Phillips <evp@xxxxxxxxxxx>

Further on in the paper they disclose the principles of their marvellous discovery:

"The basis of this method is that two same-frequency resonant circuits tend to couple, while interacting weakly with other non-resonant elements." If they intended to give ANY recognition to Tesla and had done ANY serious research about "prior art" they would have added something like "as demonstrated on a large scale by Tesla in his Colorado Springs experiments in 1899". Obviously they had NO idea of Tesla's ideas or the extent of his efforts.
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I just did a quick check to see what is in some of my earlier "wireless" reference books. Zenneck's "Wireless Telegraphy", originally published in 1906, has an extensive discussion. Pierce's "ELECTRIC OSCILLATIONS AND ELECTRIC WAVES" (1920) devotes six chapters to the subject of "The free oscillation of two coupled resistanceless circuits", discusses in considerable detail and in more familiar terms their "eigenmodes of the combined system" and gives many references to the subject dated before 1900. The first is Lord Rayleigh's "Theory of Sound" which I don't own. I'd be willing to bet he mentioned coupling between resonant acoustic devices.

And then, there's the famous "coupled pendulum" thing, which I think was analyzed even earlier.



One reference which Soljacic and crew should have noted is readily available. It is "Amplitude Relationships in Coupled Circuits", E. Leon Chaffee, from a 1916 issue of the Proceedings of the Institute of Radio Engineers. Their figure of merit "k/sqrt(Gamma 1 Gamma 2)" appears in Pierce and probably in Chaffee in the form more familiar to radio engineers - "k sqrt (Q1 Q2)" which can be found in any radio textbook.

In summary, except perhaps for their discussion on dielectric resonators, there's nothing new here except the obscure terminology and beautiful pictures. Those cats didn't "recognize Tesla's efforts" - obviously they have no idea at all of what they were or how far they went over a century before their work.


Obscure terminology and beautiful pictures can lead to a life of fame and riches...