US Patent 9111725 RF/VHF impedance matching, 4 quadrant, dual directional coupler with V

A physical vapor deposition system may include an RF generator configured to transmit an AC process signal to a physical vapor deposition chamber via an RF matching network. A detector circuit may be configured to sense the AC process signal and output a DC magnitude error signal and a DC phase error signal. A controller may be coupled to the detector circuit and the RF matching network and configured to receive the DC magnitude and phase error signals and to vary an impedance of the RF matching network in response to the DC magnitude and phase error signals.