3.5 GHz WiMAX射频功率放大器的实现及其预失真模型  

Development and predistortion of 3.5 GHz WiMAX RF power amplifier

作　　者：张雷[1] 洪伟[1] 周健义[1] 翟建锋[1] 

机构地区：[1]东南大学毫米波国家重点实验室,南京210096

出　　处：《东南大学学报（自然科学版）》2010年第6期1129-1133,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(60621002);国家高技术研究发展计划(863计划)资助项目(2007AA01Z2B4)

摘　　要：针对IEEE802.16e WiMAX标准设计并实现了中心频率为3.5GHz、峰值功率为10W的LDMOS大功率射频功率放大器.采用负载牵引法确定了功放管的最佳输入和输出阻抗.各项指标的仿真结果与实测结果高度吻合.提出一种低记忆功放并结合间接学习的方法,对该功放进行行为级建模和数字预失真,同时建立了多载波信号产生和采集的软硬件平台.实验结果表明,对于三载波W-CDMA宽带输入信号,当输出平均功率为30dBm时,采用仅7个系数的Hammerstein模型,即可得到-47.5dBc的邻道泄漏(ACLR)指标,改善度达到14dB.相对于传统的预失真技术,提出的方法能够在保证预失真性能的同时减少计算量,具有良好的应用前景.A 10 W-peak 3.5GHz LDMOS（lateral diffused MOSFET） power amplifier is designed according to the 802.16e WiMAX specification.The load-pull technique is used in decision of the best input/output impedances of the power transistor.The simulated values are in agreement with the experimental results.A method based on memory effect minimization and indirect learning is proposed and applied successfully to the behavioral modeling and digital predistortion of the implemented power amplifier.The workbench of muti-carrier signal generation and collection is also constructed.The experimental results show that a specification of-47.5dBc,with an improvement of 14dB,can be achieved for the power amplifier characterized by a Hammerstein model with only seven coefficients,driven by three-carrier W-CDMA wideband signal with an average output power of 30dBm.Compared with conventional digital predistortion technique,the computational complexity can be reduced while high performance is maintained when the proposed method is adopted,which shows its promising application.

关 键 词：射频功率放大器 负载牵引 WIMAX 行为级模型 预失真 

分 类 号：TN722.75[电子电信—电路与系统]