Methods and apparatus are provided to improve the efficiency of an outphasing amplifier through modulating the phase angle of a reflected signal in the outphasing amplifier. An outphasing amplifier includes a first amplifier and a second amplifier. A circulator is provided having a first port coupled to an output of the outphasing amplifier, a second port coupled to a load and a third port coupled to a phase shifter. The phase shifter is configured to provide a different phase angle of a reflected signal from the phase shifter to the outphasing amplifier through the circulator.