基于双阻抗匹配的宽带Doherty功率放大器设计

摘要

To meet the design requirements of high-efficiency and broadband of power amplifiers in wireless communication systems employing modulation signals with high peak to average power ratio (PAPR),an improved Doherty power amplifier (DPA) was investigated.To achieve the impedance transformations both in low power region and at saturation,a two impedance matching network design was proposed to simulate and design the main and auxiliary output matching networks,which could simplify the load modulation network of DPA and extend the bandwidth.The wideband DPA with 2.30 ～2.80 GHz was designed and measured,and the proposed method availability was verified.The results show that the designed DPA has the gain fluctuation less than 2 dB and the saturated output power more than 43.5 dBm over the frequency band of 2.30 ～ 2.80 GHz,while the saturated efficiency is from 66％ to 71％ with 6 dB back-off efficiency from 48％ to 59％.The designed wideband DPA can satisfy the efficiency requirement of future wireless communication systems employing modulation signals with high PAPR.%为了满足采用高峰均比调制信号的未来无线通信系统中功率放大器高效和宽带的设计需求,研究了一种改进的宽带Doherty功率放大器设计方法.为了实现Doherty在功率回退和饱和输出时的阻抗变换,提出了一种双阻抗匹配网络设计方法来仿真设计主路和辅路输出匹配网络,从而简化了负载调制网络,展宽了带宽.实现并测试了一个2.30～2.80 GHz宽带Doherty功率放大器(DPA),对所提出方法的有效性进行了验证.结果表明:所设计的宽带DPA在工作带宽内增益波动小于2 dB,饱和功率大于43.5 dBm,饱和时的峰值效率为66％～71％,6 dB回退时的效率为48％ ～ 59％,可满足未来无线通信系统中对高峰均比调制信号高效率放大的要求.