宽带功率放大器的非线性研究

A Study on Nonlinear Distortion of Broadband Power Amplifier

功率放大器更多时候是工作在饱和区,此时其非线性特性成为需要考虑的重要因素之一。在宽带功率放大器中,低频段信号的二次谐波也在其工作频带之内。当前级功放模块产生的二次谐波与基频信号同时进入末级功放时,产生的二阶交调信号频率与基频相同,对输出造成影响。文中从理论上分析了放大器的非线性表现形式以及产生的机理,介绍了X参数的优势,利用NVNA网络分析仪提取X参数,并且使用ADS软件进行谐波平衡仿真,研究了宽带功率放大器中二次谐波的相位对基频功率的影响。

Power amplifier works more often in the saturated zone, at this point the nonlinear characteristics become one of the im-portant factors to consider.In the broadband power amplifier, the second harmonic wave of the low frequency signal is also in the working band.The second-order intermodulation signals produced by the second harmonic and the fundamental frequency will cause an effect to the output.The nonlinear characteristics of broadband power amplifier and the explanations of nonlinear distortion are discussed in this paper.Then the advantages of X-parameter extracted with NVNA network analyzer is introduced in detail.The influence of the phase of the second harmonic in broadband power amplifier is studied with the help of simulation software ADS.