Patent ID: RE39051

Claim:
Fuzzy logic method of tuning an RF a radio frequency ( RF ) matching network of the type having an input at which is applied RF power at a given frequency and at a given impedance, and an output which applies said power to an RF load having a non-constant impedance, said matching network including a phase-magnitude error detector means providing a phase error signal and a magnitude error signal related respectively to impedance phase angle error and impedance magnitude error, and said matching network comprising at least a first variable impedance device having a driven element for varying the impedance thereof and a second variable impedance device having a driven element for varying the impedance thereof; the method comprising: supplying said phase and said magnitude error signals to a fuzzy logic controller, wherein each of said error signal signals has a magnitude and direction , ; applying each of said phase and magnitude error signal signals to a fuzzy logic inference function based on a number of overlapping fuzzy sets, and where the a value of each of said phase and magnitude error signal signals enjoys membership in one or more fuzzy sets; applying fuzzy logic rules to said phase and magnitude error signals according to the said one or more fuzzy sets for which said first and second phase and magnitude error signals enjoy membership; obtaining drive signal values based on said fuzzy logic rules for each of said phase and magnitude error signals; weighting said drive signal values according to the respective one or more fuzzy sets inference functions for which said phase and magnitude error signals enjoy membership; and combining said weighted drive signal values to produce an output drive signal for the the driven element of said first variable impedance device driven element .