Abstract: The invention provides an RF power amplifier with post-distortion linearizer. The power amplifier includes a main amplifier, an auxiliary amplifier and a phase compensator. The first amplifier has a first input end and a first output end and operates in class A or AB. The auxiliary amplifier has a second input end and a second output end and operates in class B or C. The second output end connects the first output end to form a signal output end. The phase compensator has a third input end and a third output end and compensates a phase difference between the main and auxiliary amplifiers to make outputs of the two amplifiers opposite in phase. The third output end connects the second input end. The third input end connects the first input end to form a signal input end.

Abstract: The invention proposes a lumped constant compensated high/pass balun (balance line to unbalance line transition). The proposed circuit can be used in microwave integrated circuit(MIC) and mononolithic microwave integrated circuit(MMIC) designs. The basic operating principle of the proposed circuit is to use two sets of lumped type high pass and low pass filters to synthesize a microwave balun. The first filter set provides the wide band 180.degree. phase difference property for the balun circuit. The amplitude imbalance of the balun is compensated by the other filter set. The advantage of the proposed circuit is to replace the bulky and non-planar distributed balun or traditional transformer in low microwave frequency range.