射频功率放大器前馈宽频带线性化技术的研究

Realizable Solution to Enhance the Wideband Performance of Feedforward Amplifiers

摘要: 针对第三代移动通信中的功率放大器线性化技术,提出了改善线性化带宽的解决方案。该方案通过减少前馈环路中的时延波动来提高互调失真分量的宽带对消特性,同时采用相关复解调来检测残留导频。研制了射频功率放大器,前馈对消环路和信号检测电路,用数字信号处理芯片实现了相关的自适应算法。仿真和实验结果表明,该技术能够在宽频带内对LDMOS高功率放大器的三阶互调(IMD3)改善25dB,对四载波的W-CDMA信号的邻近信道功率泄漏比(ACLR)改善17dB。

Abstract: Special and practical considerations for enhancing the wideband intermodulation cancellation performance are presented and experimentally verified.Delay ripple over wideband is minimized by input matching and isolation technique.Complex demodulation circuit is designed to extract the two-tone pilot precisely.Software and digital signal processor(DSP) board are developed for signal detect and loop optimization.The IMD3 improvement of 25dB under two-tone test over wideband and ACLR improvement of 17dB under WCDMA four-carrier signal test are achieved for LDMOS high power amplifier.