On Thu, 24 Dec 2009 16:23:05 -0500, John Ferrell
wrote:

I have been successful at modeling and then constructing transmitter
matching circuits at low power with common sizes of capacitors. Now I
want to move up to the 1 KW power level. Inductors are easy enough to
homebrew but capacitors are both expensive and scarce. Anyone have
ideas or maybe experience in this area?

Lots of idea, but the only high power experience I've had is design of
a VMOS NMR power amp in the early 1980's. Reading between your lines,
my guess is that you're building a tube amplifier.

DigiKey has a good selection of High Voltage units (3 KV Plus) at
modest cost but considering their size and the losses expected in the
capacitors I don't think they can dissipate the heat...

John Ferrell W8CCW

For high voltage and high power, vacuum caps are a good way to go:
http://en.wikipedia.org/wiki/Vacuum_variable_capacitor

There are also porcelain capacitors:
http://www.atceramics.com/products/power_capacitors.asp

There are ceramic dielectic high voltage caps but they tend to be more
lossy than vacuum or porcelain.

Jennings vacuum caps. The voltages in the table are in Kv.
http://www.jenningstech.com/ps/jen/caplist.cgi

If you want to make your own, there are always Leyden Jars and window
glass with alternating layers of aluminum foil. I've used both for
Tesla coils.

I suggest you look at various existing KW amplifier designs and see
what they use.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558