Linear filter assisted envelope memory polynomial for analog/radio frequency predistortion of power amplifiers

In this paper, a linear filter assisted envelope memory polynomial (EMP) architecture, for use in a low power analog/radio frequency (RF) predistortion scheme, is presented. The linear filter and the EMP are combined to compensate for the linear memory distortion and the dynamic non-linearity exhibited by an RF power amplifier (PA) driven by wideband modulated signals. A 20-W wideband GaN Doherty PA was used to assess the proposed architecture´s performance experimentally. The addition of the linear filter improved the performance of the EMP for wideband signals to the extent that results were comparable to those of the memory polynomial approach, while maintaining the structural simplicity of the EMP approach.