Abstract: With the continuous development of the communication system, the fifth generation mobile communication system (5G) technology has higher requirements for radio frequency power amplifier(RF PA) in terms of power consumption, delay, bandwidth and so on. Although the traditional analog predistorter can improve the nonlinearity of the RF PA, it also has a certain insertion loss, resulting in decrease of the RF PA gain. In order to solve the loss problem, a quarter wavelength impedance converter is added at the wave nodes on both sides of the nonlinear device to match the impedance, which can suppress the intermodulation distortion and reduce the insertion loss. In the experiment, Doherty RF PA operating at 3.5 GHz is linearized by the proposed analog predistorter under a 100 MHz bandwidth 5G NR signal. The test results show that the analog predistorter improves the adjacent channel power ratio of power amplifier by more than 14 dB, and the insertion loss is less than 3 dB.