基于GaN HEMT的高线性星载Doherty功率放大器设计

Design of High Linear Space-Borne Doherty Power Amplifier Based on GaN HEMT

摘要: 在射频通信链路中,功率放大器决定了发射通道的线性、效率等关键指标。卫星通信由于是电池供电, 对功率放大器的工作效率要求比较高。文章基于GaN HEMT 晶体管采用对称设计完成了一款高效率的Doherty功率放大器。测试结果表明:该Doherty 功放的功率增益大于29 dB;1 dB 压缩点功率(P_{1 dB})大于35 dBm;在35 dBm 输出时,其功率附加效率(PAE)大于47.5%,三阶交调失真(IMD3)大于35 dBc;在功率回退3 dB 时,其PAE 大于37%,IMD3 大于32 dBc。

Abstract: The linear & efficiency of the transmitting channel in the RF(Radio Frequency) communication link depends on the power amplifier (PA). Because it is battery powered, satellite communication requires higher efficiency of power amplifier. In this paper, a high linear Doherty power amplifier is designed and fabricated based on GaN HEMT. The test results show that the power gain of the designed Doherty PA is greater than 29 dB; the P_{1 dB}(1 dB compression point) is larger than 35 dBm; the power-added-efficiency (PAE) is larger than 47.5% and the third-order intermodulation distortion (IMD3) is larger than 35 dBc at the 35 dBm working status; meanwhile, the PAE is larger than 37%, IMD3 is larger than 32 dBc, respectively at its 3 dB output power back-off working status.