基于连续型功率放大器理论,提出一种高效低谐波失真宽带功率放大器的设计方法,并采用GaN高电子迁移率晶体管(HEMT)器件设计了验证电路。结合连续型功率放大器理论和多谐波双向牵引技术,找到一簇最佳负载阻抗值,并运用切比雪夫低通滤波器形式的阻抗变换器设计宽带匹配网络。偏置电路采用双扇形开路微带线和滤波电路相结合的方法进行设计,以减小电路尺寸和扩展具有高输入阻抗偏置电路的带宽。实验结果表明,在1.7~2.7GHz工作频带内,功率附加效率为50%~60%,输出功率大于4W,增益为(14±0.9)dB,二次谐波失真小于-25dBc,三次谐波失真小于-60dBc。
Based on the continuous power amplifier (PA) theory, a design method of the broadband power amplifier with high efficiency and low harmonic distortion was presented and a test cir- cuit was designed using GaN high electron mobility transistor (HEMT) device. Combined with continuous PA theory and multi-harmonic bilateral-pull technology, a family of optimal load impedances was obtained. Using Chebyshev low-pass impedance transformation, broadband matching network was designed. Combined with butterfly stub and filter circuit, biasing circuit was designed, in order to de- crease circuit dimension and extend bandwidth of the high input impedance biasing circuit. Experimental results show that from 1.7 GHz to 2.7 GHz, the power added efficiency (r/PAE) is 50%--60% with ( 14±0.9) dB power gain, the output power is more than 4 W, the second harmonic distortion is less than -25 dBc and the third harmonic distortion is less than -60 dBc.