微波功率放大器非线性特性分析

Analysis of Nonlinear Distortion of Microwave Power Amplifiers

为判断微波功率放大器非线性失真的主要影响因素,首先,在传统幂级数模型的基础上对功率放大器的非线性幅度失真和相位失真进行拟合,基于包络分析法给出了功率放大器非线性失真与幅度和相位失真间的解析关系;其次,对幅度失真和相位失真引起的非线性失真进行了分析,给出了两者之间的等效失真关系式,据此可对任意给定的功率放大器进行分析,以确定非线性失真的主要影响因素,并用于指导模拟预失真线性化器的设计与调试;最后,通过对一Ka频段行波管放大器的非线性测试及模拟预失真线性化,验证了所提出的功率放大器非线性分析的正确性及幅相等效失真关系式的有效性。

In order to determine the main factors of nonlinear distortion of a microwave power amplifier,the amplitude and phase distortion of the power amplifier are fitted based on the power series model firstly,and analytical relations between nonlinear distortion and amplitude / phase distortion are given based on the envelope simulation. Secondly,the nonlinear distortion of power amplifier caused by amplitude and phase distortion is analyzed respectively,and an equivalent distortion formula is given,which can be used to estimate the main factor of the nonlinear distortion and then guide the design and debugging of its analog predistortion linearizer. A Ka- band travelling wave tube amplifier( TWTA) is measured and linearized by an analog predistortion linearizer,which verifies the correctness of the analysis on the nonlinear distortion and the effectiveness of the equivalent distortion formula between amplitude distortion and phase distortion.