矢量网络分析仪硬件性能对测量精度的影响分析

Analysis of the Influence on Measurement Accuracy Caused by VNA Hardware Performance

文中通过深入分析矢量网络分析仪S参数测量过程中的误差来源,建立了误差项与硬件性能的对应关系,在此基础上,通过将原始测量值看作误差项的多元函数,在各误差项理想值附近保留泰勒级数线性项作为合理估计,分析了原始S参数测量结果偏差与误差模型中每个误差项之间的关联程度。对其解析式中除原始测量值以外的其他项使用增量法,求解了最终S参数测量结果偏差与各误差项之间的关联程度,由此确定了每个硬件性能引起的最终测量偏差的大小。最后使用Keysight N5227A和Ceyear 3671E两台矢量网络分析仪,在相同的校准条件下对参数已知的待测网络进行测量,通过对比最终测量结果,检验方法的正确性和有效性。

By deeply analyzing the source of error in the S-parameters measurement process of vector network analyzer(VNA),in this paper an appropriate corresponding relationship is then established between error terms and hardware performances.On this basis,the relevance between the deviations of raw measured S-parameters and error terms are analyzed by regarding the raw and final measured values as the multivariate functions of the error terms,with the linear terms of Taylor′s series as reasonable estimations of the error near the ideal values of the error terms.Increment method is utilized for other items except original measurement in this analytical expression to calculate the relationship between the deviations of final S-parameters measurements and error terms.Hence,the deviation values in measurement results attributed to the hardwave performances are determined.Finally,two different VNAs(Keysight N5227A and Ceyear 3671E)are utilized to measure the network under test with known parameters serving the same calibration steps.The correctness and effectiveness of the method are verified by comparing the final measurement results.