为有效指导前馈超线性功率放大器的工程调试与优化, 分析了元器件非理想情况下前馈功放的线性化性能及优化指标。首先, 通过简化的环路模型, 在不考虑误差功放畸变的条件下, 推导了线性度与支路幅度、相位失配及延迟失配的理论数值关系, 并分析了延迟失配对线性化带宽及抑制比的影响; 接着, 在考虑误差功放畸变的基础上定义了有效对消比, 详细分析了系统三阶交调畸变的极限对消能力。最后, 基于设计的前馈线性功放进行了优化分析。实验结果表明, 设计的功放线性度改善了36.23 dB。

In order to guide the engineering commissioning and optimization of feedforward super linear power amplifier, this paper analyzes the feedforward power amplifier linearization performance and optimized parameters when the components are not ideal. First of all, the theoretic numerical relations of the linearity and branch amplitude mismatch, phase mismatch and delay mismatch are derived, without considering the error power amplifier distortion conditions, which is based on the simplified loop model. The relation of cancellation ratio, delay mismatch and linearization bandwidth is derived. Then, the effective cancellation ratio is defined based on considering error power amplifier distortion. The cancellation ability of third order inter-modulation distortion(IMD3) is analyzed in detail. Finally, the optimization theory is analyzed based on the designed feedforward linear power amplifier. The experimental results show that the amplifier linearity improves 36.23 dB.