Patent ID: 6545542
Filing Date: 2003-04-08
Classification: H03F

Abstract:
A power amplifier comprising:a first balun including an input section that inputs a combined signal combining two signals of different frequencies, a first output section that outputs a first signal having a first phase, and a second output section that outputs a second signal having a second phase opposite to the first phase; a first amplifier that outputs a first amplified signal containing a differential frequency component of the two signals, by receiving and amplifying the first signal; a second amplifier that outputs a second amplified signal containing the differential frequency component of the two signals, by receiving and amplifying the second signal; a second balun including a first input section, a second input section, and an output section that outputs a combined signal comprising the signal entered from the first input section and from the second input section; a coupler comprising an impedance element having low impedance with respect to the differential frequency component through which the differential frequency component contained in the second amplified signal is input into a first amplification path reaching the first input section of the second balun from the first output section of the first balun via the first amplifier, wherein the differential frequency component is reduced and the first amplified signal with the reduced differential frequency component is entered in the first input section of the second balun; and the differential frequency component contained in the first amplified signal is input through the coupler into a second amplification path reaching the second input section of the second balun from the second output section of the first balun via the second amplifier, wherein the differential frequency component is reduced and the second amplified signal with the reduced differential frequency component is entered in the second input section of the second balun.