Study and minimization of the Out-phasing amplifiers nonlinearity

This paper deals with the minimization of source of nonlinearity in out-phasing amplifiers, which was widely reported in previous publications. The load modulation, produced by the lossless combiner, leads to a high sensitivity to the reactive part of the two transistors´ output impedance attributed to the extrinsic parasitics. These parasitics introduce an unbalance between the two branches and contribute to the nonlinear behavior. The minimization of such parasitics allowed a significant improvement in the linearity of the amplifier