The AM-PM conversion model as a phase statement of compression and desensitization in highly linear multicarrier power amplifiers

In this article, a novel AM-PM conversion model is compared to the classical behavioral quadrature one. The proposed model can be seen as a phase statement of compression and desensitization. These two models are closely related. However, the proposed method does not have the limitations considered in the classical model, which can be seen in the investigation of the AM-PM conversion introduced in a given carrier due to the presence of several signals, as is the case in multicarrier amplifiers. The method allows us to find the design conditions to reduce the AM-PM conversion introduced by nonlinear circuits. To show the dependence of the AM-PM conversion as a function of several input tones and frequency spacing, which is not considered in the classical model, the performance of medium power BJT and GaAsFET operating at 900 and 1900 MHz, is investigated when one, two, and three tones are simultaneously fed at the input.