一种用于5G通信的高稳定双模功率放大器

采用国产40 nm CMOS工艺,设计了一种用于5G通信的28 GHz双模功率放大器。功率级采用大尺寸晶体管,获得了高饱和输出功率。采用无中心抽头变压器,消除了大尺寸晶体管带来的共模振荡问题。在共源共栅结构的共栅管栅端加入大电阻,提高了共源共栅结构的高频稳定性。采用共栅短接技术,解决了大电阻引起的差模增益恶化问题。在级间匹配网络中采用变容管调节,实现了双模式工作,分别获得了高功率增益和高带宽。电路后仿真结果表明,在高增益模式下,该双模功率放大器获得了20.8 dBm的饱和输出功率、24.5%的功率附加效率和28.1 dB的功率增益。在高带宽模式下,获得了20.6 dBm的饱和输出功率、22.6%的功率附加效率和12.2 GHz的3 dB带宽。

A Dual-Mode High-Stability Power Amplifier for 5G Communication

A dual-mode 28 GHz power amplifier (PA) for 5G applications was designed in a domestic 40 nm CMOS process. The large-sized transistors were used in the power stage to obtain higher saturated output power. The common-mode oscillation problem of power amplifier caused by large size transistors was eliminated by using non-center tapped transformer. A large resistor was utilized at the gate of the common-gate transistor in the cascode topology to improve high frequency stability. The common gate shorting technique was applied to solve the differential gain loss produced by this large resistor. A varactor was used in the inter-stage matching network to realize a dual-mode switching, so high power gain and wide bandwidth were obtained respectively. The post-circuit simulation results showed that, in high gain mode, the dual-mode PA achieved a saturated output power of 20.8 dB, a power added efficiency of 24.5% and a power gain of 28.1 dB. In high bandwidth mode, a saturated output power of 20.6 dBm, a power added efficiency of 22.6% and a 3 dB bandwidth of 12.2 GHz were obtained.