一种使用矢量网络分析仪的阻抗测量改进方法

基于反射法理论提出了一种使用矢量网络分析仪测量集总参数元件阻抗的方法,引入阻抗匹配电路,拓宽了矢量网络分析仪的阻抗测量范围.通过对匹配电路二端口网络模型中参量A的分析,给出相应的被测元件的阻抗计算式,消除了夹具对测量结果的影响.采用矢量网络分析仪直接测量法和该阻抗测量法分别测量了5种不同阻值的金属膜电阻,结果表明,该阻抗测量方法的测量精度高于矢量网络分析仪直接测量的精度,可在30 kHz～100 MHz频率范围内实现几欧至千欧阻抗的精确测量.

An Improved Method for the Measurement of Impedance with a Vector Network Analyzer

Based on the reflection method theory,a method to measure impedance of lumped elements using a vector network analyzer (VNA) is presented. An impedance matching circuit is introduced to extend the impedance measurement range of VNA. The mathematic expression for calculating the impedance of a device under test (DUT) is obtained by analyzing 'A' parameter of two port network model in the circuit, and the influence from the jig is eliminated. Five types of metal film resistors, which are classified by their resistance, are tested by both direct measurement using a VNA and the method presented. The results show that this method has higher accuracy than the direct measurement method and can accurately determine the impedance from several ohms to thousand ohms in the frequency range of 30 kHz to 100 MHz.