中文摘要：

为解决射频及微波接触部件无源互调机理研究中直流模式无法在强线性背景中测量到微弱的非线性电流电压关系这一问题,提出了一种新的基于交流激励的测试方法。首先通过理论推导得到了具有微弱非线性特性的部件在交流电压激励下的电流电压关系表达式;然后根据该方法对由同一个二极管并联不同电阻组成的样品进行了测试,通过测量各阶谐波的信号幅度并进行相关计算,得到了强的线性项和非线性项的系数,进一步根据推导出的公式计算得到了样品的电流电压曲线和来自于二极管的电流电压曲线的非线性部分。测试和计算结果表明：该方法能够获得比线性部分低3-4个数量级的非线性部分电流,这是传统的直流方法无法测量到的;对不同样件计算所得的来自同一二极管的电流电压曲线的非线性部分是相等的,证实了该方法测量强线性背景中弱的非线性电流电压关系的可行性。该方法可为无源互调非线性机理的研究提供新的测量手段。

英文摘要：

A new method based on AC excitation is proposed to characterize the weak nonlinear current-voltage relationship in huge linear background,which is hardly measured by the DC method in the study of passive intermodulation mechanism of RF and microwave components.The current-voltage relationship of the nonlinear system is firstly analyzed when AC voltage is applied and its expression is derived,then samples consisting of a diode in parallel with different resistors are measured The coefficients for linear and nonlinear parts are calculated from the measured amplitude of harmonics with different order,the current-voltage relationship of samples and the weak nonlinear part of the current-voltage relationship coming from diode are also obtained from the resulting expression.Results show that the proposed method obtains a weak nonlinear part of current which is 3-4orders smaller than the linear part in magnitude,andexhibits advantage of the method over traditional DC method.Moreover,the calculated weak nonlinear parts of currents coming from the same diode with different samples are almost equal,and the practicability of the method is confirmed.The method will offer a new way for investigating nonlinear conduction mechanism that is resulted in passive intermodulation.