SMT Design Issues for 2225 Capacitors in High Power RF | 8 August, 2011
We are building a plasma diagnostic to monitor MHD phenomena in tokamak.
As part of the development, we need high-voltage, high-power RF capacitors to tune and match an inductive load. This application is similar to a small induction heater, with the following operational parameters:
RF Power 2-4 kW
Frequency 50-300 kHz
RF Voltage 500-1000 V
RF Current 50-100 A
Duty Factor would be 10 second pulses 10 minutes apart with continuous operation at lower power for testing and calibration.
We need to build two digitally adjustable capacitors (0.6-5.0 uF and 0.1-9.0 uF) out of smaller surface mount components. We expect to use approx one thousand 2250 capacitors on twenty 6U pc boards.
Does anyone have a reference design or even a photograph for board like this. I've been searching at MRI and Ham radio websites, but I haven't found anything useful yet.