Linearization of Power Amplifier Based on Digital / Analog Hybrid Predistortion Technology

With the increase of the mobile communication signal bandwidth, the traditional digital predistortion (DPD) linearization technology for the power amplifier (PA) is more and more limited by the sampling rate. In order to make the linearization effect better, a hybrid predistorter combining the DPD and the analog predistortion (APD) is proposed in this paper. Using the advantages of the wide-bandwidth of the APD and the high linearization ability of the DPD, the APD and DPD are combined to compensate the nonlinearity of the PA. Due to the limitation of sampling rate of the experimental equipment, a 5 G NR signal with 60 MHz bandwidth is used to verify an RF PA with 3. 5 GHz center frequency. The experimental results show that the proposed hybrid predistorter not only has better nonlinear correction performance than single digital predistorter and analog predistorter, but also can improve the out-of-band intermodulation distortion which could not be improved due to the limitation of sampling rate.