A Simplified Polynomial Behavioral Model for Linearization of Envelope Tracking Power Amplifier

In this work, a simplified polynomial behavioral model is proposed to improve the linearity of an envelope tracking power amplifier (ET-PA). Theoretical analysis reveals that the third-order and the fifth-order intermodulation (IM) components can be reduced if properly shaping the dynamic drain voltage. Based on a two-tone signal test, the proposed model is constructed for the ET-PA, and then applied to predict the optimal shaping function for linearity enhancement. With aid of the proposed model, the ET-PA achieves a reduction of $8.2 \mathrm{~dB} / 9.4 \mathrm{~dB}$ at the lower and upper third-order IM components, and a 6 dB back-off power-added efficiency (PAE) higher than $40 \%$.