Re: Inverse Square 'law' Re: About wireless energy transfer

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Original poster: Ed Phillips <evp@xxxxxxxxxxx>

Original poster: <davep@xxxxxxxx>

>...rectenna...
I shorthanded, perhaps confusingly.
As noted, the rectenna, itself is quite
conventional.  I referred to the downlink source.

>inverse square for a 'well collimated' beam.
 Skipping for the moment the engineering detail of how to,
 I tend to wonder where the energy goes, in the _specific_
 hypotehtical, case.

 How does a well collimated beam differ, eg, from a
 waveguide guided beam?
  (skipping, for discussion purposes, absorption losses in
   waveguide case...)

 Or we may be getting too far OT?
 Feel free to drop.
  best
   dwp"

   In a collimated beam most of the energy is in the main beam, 
whose exact shape (intensity vs angle) depends on the size of the 
radiating aperture and the distribution of power across it.  In 
general there will also be "side lobes" of radiation at other angles 
which contain energy too.  A very very rough rule of thumb for many 
antennas is that half of the total power will be in the main beam and 
half in the sum of all of the sidelobes.

   In the case of the waveguide all of the energy is contained 
within the buide and there is no real beam to diverge.  Neglecting 
losses all of the transmitted energy will arrive at the far end.

Ed