WCDMA直放站应用的线性化功率放大器

A linearized power amplifier for WCDMA repeater application

采用一种应用三阶交调信号发生器产生的交调信号反相对消掉功率放大器自身的交调分量改善功率放大器的线性度的射频预失真方法，设计和实现了应用于WCDMA直放站的预失真线性化功率放大器．实测结果表明，在2．11～2．17GHz频带内，功率放大器在输入1MHz间隔的双音频信号条件下，输出功率42dBm，增益56dB，三阶交调失真比达到-70dBc，三阶交调改善量大于25dB．功放输入-14dBm的双载波WCDMA信号时，输出功率达到42dBm，相邻信道功率比（ACPR）达到-50dBc，改善量达到9dB．

In this paper, a RF predistortion approach to linearize power amplifier is presented which utilizes the third-order intermodulation signal generated by a third-order intermodulation signal generator to cancel the intermodulation component of power amplifier itself. A high performance linearized power amplifier for WCDMA repeater application has been designed and implemented. The measurement results show that the IM3 distortion rate of the power amplifier reaches - 70 dBc and the improvement in IM3 cancellation is more than 25 dB for two-tone signal with 1 MHz signal spacing in the frequency range from 2.11 GHz to 2.17 GHz at a 42 dBm output power. For a forward-link two-carrier WCDMA signal at a - 14 dBm input power level, the predistortion power amplifier delivers an adjacent channel power ratio of - 50 dBc at a 42 dBm average output power with a cancellation of 9 dB.