Apparatus for matching a variable load impedance with an RF power generator impedance

An impedance matching network coupled to a transmission line, said transmission line coupling a radio frequency power generator to a load, said impedance matching network comprising:

• a phase detector coupled to said transmission line, said phase detector detecting a phase shift in a voltage and a current on said transmission line;
• a frequency synthesizer circuit coupled to said phase detector, said frequency synthesizer circuit changing the frequency of said voltage depending on said phase shift in said voltage and said current on said transmission line detected by said phase detector;
• a magnitude detector coupled to said transmission line, said magnitude detector detecting an impedance on said transmission line;
• a plurality of capacitors coupled to said transmission line parallel to said load;
• an inductance coupled to said transmission line in series with said load;
• a capacitance coupled to said transmission line in series with said load, said capacitance, said plurality of capacitors, and said inductance forming an L-type impedance matching network;
• a plurality of switches, each coupled to one of said plurality of capacitors, said plurality of switches coupling and decoupling said plurality of capacitors to a ground depending on said impedance of said transmission line detected by said magnitude detector;
• and,
• a controller coupled to said magnitude detector and said plurality of switches for controlling said plurality of switches depending on said magnitude of said impedance on said transmission line.