非线性功放记忆效应分析与仿真

Analysis and simulation of memory effects for nonlinear power amplifier

为了证实非线性功放记忆效应的存在同时为了设计和优化功放以减小记忆效应,通过理论推导和ADS仿真的方法分析了不同间隔的双音输入和调制输入的情况下电记忆和热记忆效应的存在,同时提出了一种优化功放记忆效应性能的方法。理论分析和仿真结果表明功率放大器上下边带不平衡和互调失真幅度依赖于包络频率和结温,结果和测量的结果是一致的,说明存在电和热记忆效应。可以通过优化设计功放来减小记忆效应,但不能完全消除记忆效应。系统级仿真中非线性功放模型必须考虑记忆效应。

In order to verify memory effects of nonlinear power amplifier （PA） and to design and optimize PA with reducing memory effects, this paper analyzes existence of electrical and thermal memory effects with different tone spacing two-tone input signal and modulated signal source through mathematical derivation and advanced design system （ADS） software simulation, and presents a method which can optimize PA with memory effects. Theoretical analysis and simulation results demonstrate that asymmetries in lower and upper sidebands and IMD magnitude variation depending on envelope frequency and junction temperature can appear, these results are in accordance with measurement results, and show that electrical and thermal memory effects exist. It can reduce memory effects through optimizing PA design, but can＇t completely cancel memory effects. So, memory effects of nonlinear PA model are considered in system-level simulation.