Patent ID: 7046085

Claim:
A power amplifier comprising: a first amplifier element configured to amplify a first input signal of a first frequency, the first amplifier element including a first input terminal which receives the first input signal, and a first output terminal which outputs a first output signal obtained by amplifying the first input signal; a second amplifier element configured to amplify a second input signal of a second frequency, the second amplifier element including a second input terminal which receives the second input signal, and a second output terminal which outputs a signal obtained by amplifying the second input signal; a power supply input terminal connected to a direct-current power supply; a common power supply path including an end connected to the power supply input terminal, and another end; a first individual power supply path including an end connected to the another end of the common power supply path, and another end connected to the first output terminal, the first individual power supply path having a first impedance; a second individual power supply path including an end connected to the another end of the common power supply path, and another end connected to the second output terminal, the second individual power supply path having a second impedance; a first output matching circuit connected to the first output terminal of the first amplifier element; and a second output matching circuit connected to the second output terminal of the second amplifier element, wherein: a first amplifier element and the second amplifier element are controlled exclusively to operate the first amplifier element and the second amplifier element; and the common power supply path, the first individual power supply path and the second individual power supply path, the first output matching circuit and second output matching circuit have respective impedances, each of the respective impedances being set to a value so that a real part of a synthesis impedance viewed from one selected from the first amplifier element and second amplifier element that is in operation, to a corresponding one selected from the first and second individual power supply paths, is greater than a real part of a corresponding one selected from the first output matching circuit and second output matching circuit.