基于Wiener-Arrhenius模型的行波管阴极可靠性分析

Cathode Reliability Analysis of TWTs Based on Wiener-Arrhenius Model

为了对行波管寿命进行快速预估,利用行波管短管在地面开展了加速退化试验。考虑到施加不同应力引起产品的退化率不同,提出了基于Wiener-Arrhenius模型的寿命分析方法。首先,以行波管阴极的发射电流为性能退化量,通过温度加速退化试验获取其阴极发射电流退化数据;然后利用Wiener过程描述行波管阴极的退化过程,使用Arrhenius模型分析样本退化量与阴极工作温度之间的关系;最后使用极大似然估计和最小二乘法,估计行波管阴极在正常工作条件下的模型参数,并对该型行波管阴极在正常工作条件下的寿命进行预估。与正常工作温度条件下利用Wiener过程模型和阴极发射电流退化数据拟合的结果进行对比,表明了本文中模型的正确性和预估结果的合理性。

In order to quickly predict the lifetime of TWTs,an accelerated degradation test(ADT)is carried out on the ground using a short vacuum tube.Considering the different degradation rate of products caused by different stresses,a lifetime prediction method based on Wiener-Arrhenius model is proposed.Firstly,the cathode emission current of TWT is taken as the performance degradation parameter,and the degradation data are obtained by temperature accelerated degradation test.Then the degradation process of TWT cathode is described by Wiener process,and the relationship between sample degradation and cathode working temperature is analyzed by Arrhenius model.Finally,maximum likelihood estimation and least square method are used to estimate model parameters under normal working conditions and the lifetime of the TWT cathode is predicted.Compared with the results fitted by Wiener process model and cathode emission current degradation data under normal operating temperature,the correctness of the model and the rationality of the prediction results are verified.