使用电流探头测量端口散射参数的方法

S-parameter Determination with Current Probes

为了避免常用测试散射参数方法的缺点,介绍了使用电流注入探头和电流测试探头测试端口散射参数的新方法。首先,利用注入和测试探头卡住输入与输出电流端口的导线,测量两个探头之间的散射参数。然后,确定注入和测试探头的特性参数。注入和测试探头可以看作理想的变压器,其特性参数确定后,可以通过校准消除其在测试过程中产生的影响。最后,将注入和测试探头之间的散射参数与探头的特性参数进行计算,可计算得导线连接的设备端口实际散射参数。利用常用方法和该方法对具体设备进行了对比测试,测试结果发现方法在10MHz以下有非常好的一致性,10与100 MHz相差≤10 dB。在上升时间≥10 ns的瞬态脉冲频谱分析中,其脉冲主频<10 MHz,可以较好地应用该方法得到理想测量结果。研究发现测量误差主要是由于电流探头的精确度限制,利用高频电流探头可以得到更好的测量结果。在电磁拓扑分析中,这种方法可以避免对系统拆解带来的误差,提供的在线测试方法,便于实施,方便测量。

This paper introduced a method of determining S-parameters with two current probes.First,current injection and measurement probes were used to clamp lines of input and output ports in order to measure scattering parameters between the two probes.Second,determine the characterization of the injection and measurement probes.which can be assumed to be ideal transformers.After the confirmation of the parameters,the error in test procedure can be calibrated.Third,by using the scattering parameters between the injection and measurement probes and characterization of probes to compute,actual result of the ports can be figured out.The paper compared the new method to traditional method,the new method had an ideal result agreement to traditional method below 10 MHz,and the result difference between two methods from 10 MHz to 100 MHz was smaller than 10 dB.The method can be used in electromagnetic effect analysis of pulse with raise time smaller than 10 ns,of which the main frequency is smaller than 10 MHz.It is fourd that the main cause of the error is the limit of the performance of probes.In topological analysis,using the method can avoid error caused by dismantlement,and provides on-line test and convinient measurement.