Broadband RF Power Amplifier with Active Load Modulation

An apparatus comprising

• a main amplifier core and at least one auxiliary amplifier core, an input signal splitter connected to the input of the main amplifier core and the input of the at least one auxiliary amplifier core, and an output combiner connected to an output of the main amplifier core and an output of the at least one auxiliary amplifier core,
• wherein the input signal splitter is configured to split an input signal into a first signal for the main amplifier core and at least a second signal for the at least one auxiliary amplifier core according to frequency dependent nonlinear input drive functions, and
• the output combiner is configured to combine output signals of the main amplifier core and the at least one auxiliary amplifier core, and to provide a continuum of optimum termination impedances of the main amplifier core for the fundamental frequency and at least one harmonic frequency over a predetermined bandwidth of operation, in a low power region, the low power region being defined by the at least one auxiliary amplifier core being inactive.