Study of AM-PM Deviation on Power Amplifier Linearization Performances for 5G Applications

This paper presents an easy method to simulate the impact of a Doherty power amplifier (DPA) Amplitude to phase (AM-PM) deviation on its linearizability using digital predistortion (DPD) system. To simulate the DPD system, the DPA is replaced by its nonlinear impulse model extracted from continuous-wave (CW) simulation. The behavioral model identification data are modified in such a way to reduce or increase only the AM-PM dispersions. This technique and linearization performances are evaluated using a MMIC 75W 3-ways DPA at 3600MHz. The purpose of these simulations is to rapidly advise the designer of the maximum AM-PM deviation that a given DPD system can compensate for. The designer will then adjust the circuit accordingly to maximize the efficiency-linearity trade-off.