How Does Wireless Power Transmission Work?

[zoki85]

There's no inverse square law problem with directed or focused EM waves energy beams. Problems are of other kinds.

 

[Baluncore]

Problems are of other kinds.

Would you include the size and aiming of the antennas as a problem?

 

[zoki85]

Would you include the size and aiming of the antennas as a problem?

Yes. Preceise beam pointing to the rectantenna site on the ground is of crucial importance in such transmission. Needless to say, it requires special technology and methods.

 

[sophiecentaur]

There's no inverse square law problem with directed or focused EM waves energy beams. Problems are of other kinds.

You cannot beat the inverse square law, once the distance is great enough. Spreading loss is always with us and using directive antennae only increases the gain in a particular direction.
The fancy stuff with metamaterials presupposed you can stick the (equivalent of a) lens between transmitter and receiver and that presupposes that you have somewhere to mount it.
"Special technology and methods" smacks a bit too much of Magic, rather than Engineering.

 

[Baluncore]

Yes. Preceise beam pointing to the rectantenna site on the ground is of crucial importance in such transmission. Needless to say, it requires special technology and methods.

I understand the incredible technical challenge of efficient microwave energy transfer from space to Earth because I have done my time in antenna design and in the tracking systems of big dish antennas for radio astronomy.

The size and surface phase accuracy of the antennas required for efficient energy transfer from space to Earth is fundamental to countering the inverse square law. Space power will be uneconomic on Earth unless we can find a practical parallel ray energy transfer mechanism.

 

[zoki85]

Spreading loss is always with us and using directive antennae only increases the gain in a particular direction.

Point is that distance is close enough so that spreading loss can be made small enough.

The fancy stuff with metamaterials presupposed you can stick the (equivalent of a) lens between transmitter and receiver and that presupposes that you have somewhere to mount it.

I am not familar with proposed use of metamaterials included anywhere in space between satellites and ground receiver.
Would you give us references?

"Special technology and methods" smacks a bit too much of Magic, rather than Engineering.

There are lot of papers published in per review journals about these technologies and their state of art. It's not magic, it can be done. Much bigger problems are very high price for installation, and question if the expense can be justifyed or not (personally, I don't so). OTOH, there are other very costly power energetic programs like ITER , which are much more important.