Re: Solar power [was Nano-Rectennas]

From: KPJ (
Date: Tue Feb 01 2000 - 04:40:01 MST

It appears as if Stirling Westrup <> wrote:

|Is there anything stopping us from making sheets of rectennae (I gather
|that is a rectifying antenna, but I'm not sure) that were designed to
|pick up wavelengths in the visible spectrum? These would have to be mighty
|small antennae, so we would have to build them with chip fabrication
|techniques or even nanotech, but they should be highly efficient and
|very long lasting solar cells shouldn't they? What technological barriers
|are currently preventing us from trying this out?

The word ``rectennę'' points at the same concept as ``rectifying antennę'' do.
Some humans use the alternative spellings "rectennas" and "antennas", though
(americanisms, I suppose).

Fact: Non-coherent (non-lasered) human visible light scatter more easily
        when sent through gas mixtures like the terran atmosphere than do
        non-coherent (non-masered) microwaves.

If one sends lasered human visible light instead of masered microwaves through
the terran atmosphere, then:

(a) One would need more power to reach the same throughput (bandwidth).

(b) The antenna (rectenna) size depends on the wave length to some degree.
        Therefore, one would need a larger antenna with human visible light
        than with masered microwaves.

NOTE: The terran atmosphere absorbs many wavelengths. Would it absorb so
        much more of the microwave radiation than of the lasered human visible
        light that the above analysis fails to give a result which matches the
        real world?

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