Electrical circuit to impedance match a source and a load at multiple frequencies, method to design such a circuit

摘要

The invention concerns a matching circuit (3) to adapt electrical impedance simultaneously for at least one pair of a higher and a lower frequencies between a plasma reactor and a generator; said matching circuit comprises at least a "load and tune" L-type stage comprising:
- a "tune circuit" (4) connected in series to the plasma reactor and comprising at least one of or both an inductor (L Tune ) and a capacitor (C Tune ) in series,
- a "load circuit" (5) connected in parallel to the series-connected "tune circuit" and load, and comprising at least one of or both an inductor (L Load ) and a capacitor (C Load ) in parallel,
the component values of the tune and load circuits are chosen such that, for the lower frequency, the matching circuit follows a negative load reactance path in a Smith chart, and for the higher frequency, the matching circuit follows a positive load reactance path in the Smith chart. The invention describes the extension of the design to enable such matching for multiple pairs of frequencies.