MASER wireless power transmission

[Kevin Reed]

I know a little about PECVD , Vapor deposition, sputtering, etc.

I am talking to NPL about the possibility of pentacene/sapphire (or diamond)

thin film MASER devices on the SBSP scale. 

I reckon if workable these could be cheaply mass produced for kilometer

scale SBSP beaming antenna.

The advantages would be much smaller ground rectenna site with coherent maser beam.

The only downside I see is working out the optics.

Kev

MASER power comes out of the cold: Researchers demo solid-state MASER capable of operating at room temperatures

MASER power comes out of the cold: Researchers demo solid-state MASER capab... Scientists from the National Physical Laboratory (NPL) and Imperial College London demonstrate, for the first ti...

MASER power comes out of the cold : News : News + Events : National Physical Laboratory

MASER power comes out of the cold : News : News + Events : National Physical Laboratory NPL and Imperial College London's work on the first solid state MASER to operate in air at room temperature ...

[Keith Lofstrom]

On Sat, Apr 02, 2016 at 08:47:12PM +0000, 'Kevin Reed' via Power Satellite Economics wrote:
> I know a little about PECVD , Vapor deposition, sputtering, etc.I am talking to NPL about the possibility of pentacene/sapphire (or diamond)thin film MASER devices on the SBSP scale. I reckon if workable these could be cheaply mass produced for kilometerscale SBSP beaming antenna.
> The advantages would be much smaller ground rectenna site with coherent maser beam.The only downside I see is working out the optics.Kev

>> MASER power comes out of the cold: Researchers demo solid-state MASER capable of operating
>> at room temperatures

That points at this 2012 paper:

http://www.nature.com/nature/journal/v488/n7411/full/nature11339.html

Behind a paywall, but it does mention a -10 dBm ( 100 μW )
output at 1.45 GHz. Very good noise figure, perhaps useful
as a signal or measurement amplifier at that frequency, but
not a good way to make > 100 MW microwave power beams.

Still, this research might lead to the high power stuff.

Keith




--
Keith Lofstrom kei...@keithl.com

[Keith Henson]

On Sat, Apr 2, 2016 at 1:47 PM, 'Kevin Reed' via Power Satellite Economics <power-satell...@googlegroups.com> wrote:

snip
 

The advantages would be much smaller ground rectenna site with coherent maser beam.

If you are going to transmit to the ground, you are up against two problems.  One is keeping the intensity down to where it will not hurt birds or can be turned into a weapon--that's around a quarter of a kW/m^2.  The other is the atmosphere transparency. 

 

The only downside I see is working out the optics.

The optics is simple.  https://en.wikipedia.org/wiki/Airy_disk

You can always scale it.  For 2.45 GHz, the disk diameter out to the first null is 10.6 km for GEO distance and a 1 km transmitting antenna.  For 24.5 GHz, the diameter of a rectenna would be a bit over a km.  The frequency is too high get through a rainstorm, but it works just fine for space to space power beaming.  If you put the transmitter in an 18,000 km orbit, you can get the rectenna down to 500 m.

The big problem is not designing power satellites or using high frequency, but getting the parts to GEO at a reasonable cost.  Skylon at high flight rates does fine to LEO ($120/kg).  Chemical fuel increases that by a factor of 2.5, and that kills the economics.  Beamed power and arcjets look like a solution.

Would you like to go through the spreadsheet?

Keith

 

Kev

MASER power comes out of the cold: Researchers demo solid-state MASER capable of operating at room temperatures

MASER power comes out of the cold: Researchers demo solid-state MASER capab... Scientists from the National Physical Laboratory (NPL) and Imperial College London demonstrate, for the first ti...

MASER power comes out of the cold : News : News + Events : National Physical Laboratory

MASER power comes out of the cold : News : News + Events : National Physical Laboratory NPL and Imperial College London's work on the first solid state MASER to operate in air at room temperature ...

--
You received this message because you are subscribed to the Google Groups "Power Satellite Economics" group.
To unsubscribe from this group and stop receiving emails from it, send an email to power-satellite-ec...@googlegroups.com.
To post to this group, send email to power-satell...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/power-satellite-economics/2073430145.1383964.1459630032719.JavaMail.yahoo%40mail.yahoo.com.
For more options, visit https://groups.google.com/d/optout.

[Keith Lofstrom]

On Sat, Apr 02, 2016 at 06:35:44PM -0700, Keith Lofstrom wrote:
> >> MASER power comes out of the cold: Researchers demo solid-state MASER capable of operating
> >> at room temperatures

A 2015 paper is open access:

Enhanced magnetic Purcell effect in room-temperature masers

http://www.nature.com/ncomms/2015/150220/ncomms7215/pdf/ncomms7215.pdf

Pg 2: ... optically pumped with a xenon flash lamp
delivering peak optical power of 70 W. ...

Pg 3: ... a strong maser burst of microwave power was
observed 20μs after the onset of the optical
pulse with a peak power of 6μW (22.2dBm) ...

Pg 4: Fig. 3 graphs the measured input and output pulses.
The optical pulse is about 6x wider than the 1.45 GHz
microwave pulse. Efficiency approximately 14e-9 .

Again, what's nifty about this work is that they've used
clever solid state materials to make a microwave maser
work at room temperature, very difficult. They will
learn things about materials that could lead to far
more efficient systems ... but not soon.


BTW, tomorrow I will attend a Portland State physics
lecture by a Lawrence Berkeley Lab researcher working
on direct bandgap lead halide perskovite solar cells;
overall efficiency 20%, but some individual grains
show 30%. Cheap common materials; I'll ask about
radiation sensitivity. My friend John Freeouf is
physics department chair, and worked on super radhard
graded junction indium phosphide cells.

[Paul Werbos]

Re -- masers.

I hate to confess ignorance on a very basic subject I SHOULD know about, since I know a lot of related stuff...

But: has anyone evaluated what maser technology could or could not do to enhance the phased array type of power beaming described in John Mankins' book, the Case for Space solar power?

The shift from centralized power collection and beaming to distributed power collection beaming, as in SPS-ALPHA, as absolutely crucial to the change from earlier 17-cents-per-kwh cost estimates to 9 cents per kwh, under the same assumptions (like $500/kg-LEO but also others). That kind of factor of two of cost reduction is absolutely essential here.

The phased array people generally do know about masers, and issues like diffraction apply to maser light as well as ordinary light, but ... is the possibility of using masers in that context a real issue or a nonissue?

=======

I should add that this is all what happens when solar power is the source of energy generation in space.

My earlier proposal to use D-D fusion instead, using the pellet designs form Perkins of Livermore and optically pumped lasers to ignite fusion, would result in more centralized actual power generation, and justify revisiting the issue of how to beam it to earth. When generation is cheaper, reducing the cost of transmission suddenly becomes more important, even if there is some loss of efficiency in transmission. 

Best of luck,

   Paul

--
You received this message because you are subscribed to the Google Groups "Power Satellite Economics" group.
To unsubscribe from this group and stop receiving emails from it, send an email to power-satellite-ec...@googlegroups.com.
To post to this group, send email to power-satell...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/power-satellite-economics/20160404082406.GA19294%40gate.kl-ic.com.