Design of Broadband High-Efficiency DPA for 5G Micro Base Station

Abstract

To meet the requirements of the 5G communication system, the Doherty power amplifier has become a research hotspot because of its peak-to-average ratio and high backoff efficiency. At the same time, with the continuous development of mobile communication technology, the traditional Doherty power amplifier has gradually been difficult to meet the needs due to its structural problems. On the one hand, due to the limitation of the 1/4 wavelength transmission line in the traditional Doherty power amplifier, it is difficult to achieve broadband. This paper uses the post-matching technology to remove the 1/4 wavelength transmission line to achieve broadband matching. On the other hand, in response to energy conservation and emission reduction, there is a growing demand to reduce power consumption in base stations. In this design, a harmonic suppression network is introduced at the output matching end to further improve the efficiency of the Doherty power amplifier. Finally, the asymmetric structure is introduced to further improve the efficiency of the power amplifier. Main and auxiliary power amplifier transistors select Cree CGH40010F and CGH40025 respectively. Based on the ADS simulation design and test, a broadband high-efficiency Doherty amplifier working in a 3.3~3.6 GHz band is designed for a 5G communication base station. The maximum saturated output power is 44.5 dBm and the drain efficiency is 67%~73%. When power fallback is 8 dB, the drain efficiency is 43%~51%.