Designing an Auto Match Unit for RF supply

[Ash Small]

I've picked up a 13.56 MHz RF generator from eBay which I plan to use for an ICP plasma project (this is what it was designed for).

I need to construct an RF coil and parallel capacitor with a resonant frequency of 13.56 MHz but I also need to construct an AMU as, as I understand it, as soon as I put a load on the coil the resonant frequency will be altered.

I understand these AMU's usually have a couple of stepper motors driving variable capacitors to maintain the resonant frequency at 13.56MHz as the load on the coil varies, but I'd appreciate some advice from someone who knows about these things regarding how I should go about designing the AMU and it's related circuitry.

I understand these AMU's operate in a similar fashion to SWR meters but that they adjust the resonance as the load varies.

Any help or advice would be greatly appreciated.

Thanks.

 

[anorlunda]

Ping @Baluncore . Can you help with this spring cleaning thread?