ELECTRICAL CIRCUIT TO IMPEDANCE MATCH A SOURCE AND A LOAD AT MULTIPLE FREQUENCIES, METHOD TO DESIGN SUCH A CIRCUIT

摘要

A matching circuit is provided 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, and includesa “tune circuit” connected in series to the plasma reactor and having at least one of or both an inductor and a capacitor in series;a “load circuit” connected in parallel to the series-connected “tune circuit” and load, and comprising at least one of or both an inductor and a capacitor in parallel; and 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.