I am desperate for 30-50W RF generator

I desperatly need a RF generator (around 30-50W). I need to purchase it or build my own generator. I have only SUS200 for my MS project and about 3 month time. Looking for a person willing to give up his old RF generator, Schematics which can help me build one myself, link to any usefull info or any advice will be appreciated.

That's a very loose specification. Are you tallking about fixed frequency or variable, 100KHz or 100GHz, with or without modulation and if with, AM, FM, PM, digital or analog?

Lot's of questions you need to answer of you want hep.

Brian.

you are a student so we will go easy on you, but you have specified very little. Nobody is going to help you unless you at least tell us the frequency.

I need this as power supply for plasma generation. Something similar to the one here:

http://www.plasmi.eu/component.php?idp=27&LANG=ENG

Preffered frequency is 13.56 MHZ fixed but other frequencies are also ok as long as to be able to creat and stabilize plasma ok. Aim is generating plasma inside our 2cm diameter X 2.5cm long quartz cylinder filled with 10^-3 torr Ar gas. Analog design should be OK and no need for computer comunication. Also power up to 100W is OK if cost does not increase too much.

Preffered output impedance is 50 ohm

Well if it's a fixed, low frequency, then it shouldn't be too terribly difficult/expensive. It can probably be built using a class E or class D (push pull) amp, using silicon or GaN switching FETs. However these switching amplifiers won't have a 50ohm output impedance (though they can be made to drive 50 ohm loads just fine).

But I don't know much about plasma generation, or what kind of special requirements that puts on the amplifier

The easy way for this is to find a HF ham operator with a 14MHz transmitter (100W variable).
You can make a resonant tank coil of 8mm copper heating tube (hardware store) to go around your gas tube, in parallel with some sort of tunable capacitor that can take the (kilovolts) that will happen.A sliding tube within a tube with plastic insulation between maybe. There are many free tools on the net to help you calculate this.

Even better is to also have the antenna matching unit that might provide a balanced feed output that gives you two nice terminals to connect to instead of the coax.

Making RF arcs happens so easily that these folk spend time and money trying to have it not happen. If you just wind a few turns from the end of a regular vertical antenna loading coil, ie without the rest of the pole on it, and turn on a little RF, it will glow.

You can also fail badly if you do not understand where the high voltage electric near-field is, but this trick is easy to do. You only need to walk under a 14MHz antenna while carrying a florescent tube to have it light up in your hand.

For you, the good thing is it can be done in hours, not weeks. It need not cost much. All the kit is there to generate a clean stable RF in one unit, and you are likely to get lots of help from the guys who will not mind helping you make something glow.

Use ARRL, qsl.net, DXzone, as keywords. Google is your friend here. Find a club near you.