L波段GaN宽带高功率放大器设计

摘要

The design and implementation of a broadband balanced power amplifier(PA) using GaN HEMT transistor is described. Working band for 1~2 GHz.90° hybrid Power combining is used to combine the outputs of two individual octave bandwidth 40 W power amplifiers. The final combining output power could reach 80 W. Load pull simulation is done, thus to obtain the optimized load impedances and provide the best trade-off between max.output power (Pout) and max.PAE. The input/output matching network is composed of multiple stepped series transmission lines and multiple open stubs. The effects of the 2nd harmonic load impedances on the efficiency are analyzed, thus to increase the efficiency over the design band. Co-simulation is done to optimize PCB layout parameter and complete the L-band power amplifier engineering. The measurement results indicate that the amplifier could provide an output power of 75~100 W, PAE of 50.5%~60%,Gain flatness of 2.2 dB, and that the measured IMD3 is greater than 25.5 dBc at a PEP output power of 60 W.%阐述了基于GaN HEMT的1~2 GHz频段的宽带平衡式功率放大器的设计方法.结构上,使用平衡式功率合成结构,将两路相同的40 W功率放大器进行正交功率合成输出80 W.利用双音负载牵引,仿真得到兼顾功率设计与效率设计的最佳匹配阻抗;使用多节阶梯阻抗变换和并联开路枝节的匹配方式,设计了输入输出宽带阻抗匹配.匹配网络设计通过分析谐波阻抗对功放效率的影响,以提高功放效率指标,并基于ADS的电磁仿真系统优化宽带匹配电路版图参数,完成L波段宽带功放设计:实测功放输出功率75~100 W,效率50.5%~60%,增益波动2.2 dB,峰值功率输出60 W,测试IM3高于25.2 dBc.