Designing Highly-linear Microwave Power Amplifiers Based

This paper shows how intermodulation distortion, IMD, sweet spots can be used as a practically meaningful technology to design highly linear microwave power amplifiers. It starts by reviewing the physical origins of these points of large signal to nonlinear distortion ratio, distinguishing the ones uniquely determined by the active device’s quiescent point – small-signal IMD sweet spots – from the ones that are dependent on the excitation level – large-signal IMD sweet spots. Then, it evaluates the main amplifier circuit parameters that are known to control these sweet spots, giving this way design guidelines for low level high dynamic range/class A amplifiers or for highly efficient and linear power amplifiers.