Design of a broadband high-efficiency Doherty power amplifier for 5G communication systems

In this paper, a novel load modulation network structure is proposed by connecting a shunt lambda/2 micro-strip line at the combiner of traditional DPA. And it can achieve wideband impedance transformation for the carrier power amplifier. In this way, the performance of the DPA is improved in both bandwidth and back-off point efficiency. A broadband high-efficiency Doherty power amplifier (DPA) is designed and fabricated for 5G mobile communication. Measurement results show that the saturated output power of the DPA is above 43 dBm in the range of 3.1 to 3.7 GHz, and the saturated drain efficiency is between 65% and 73.1%. Additionally, drain efficiency of the 8 dB power back-off is above 40%. And better than -45.6 dBc adjacent leak power ratio (ACLR) can be achieved with Digital Pre-Distortion (DPD) under 10 MHz LTE signal testing at 3.3 GHz.