双线法测量横向阻抗中双线间距及线径的影响

Effect of dual-wire distance and wire diameter on transverse impedance measurement using dual-wire method

根据双线法测量横向阻抗的原理,从理论和模拟计算两方面对双线间距、线径因素造成的系统误差进行讨论。给出谐振腔近似下双线法测量横向阻抗的等效电路,通过此等效电路对双线间距、线径因素造成的系统误差进行讨论。通过模拟计算的方法分析了双线法测量类腔体TM110模式横向阻抗时,不同双线间距、不同线径带来的系统误差,模拟计算的结果与等效电路结果分析得到的定性结果一致。模拟计算分析表明,对于管道半径为50 mm的类腔体结构,线径小于6 mm及双线距离小于50 mm时,双线间距及线径引入的横向阻抗系统误差小于8%。

The dual-wire method is a widely used transverse impedance measurement method. When the transverse imped ance of the device under test is very small, large lateral distance between the two wires and large diameter of the wires are prefered to get large signal and thus the measurement results are reliable and reproducible. However, large lateral distance and diameter would lead to large systematic error. A numerical research using HFSS were carried out on the systematic error due to the dualwire distance and diameter. Its result shows that, for moderately small dual-wire distance and wire diameter, the measured transverse impedance is smaller than the theoretical value calculated by ABCI and HFSS,and larger dual-wire distance and diameter lead to larger systematic error. In the case of a cavity-like structure with 50 mm pipe radius, the systematic error of transverse impedance measurement is less than 8% for the wire diameter less than 6 mm and the dual-wire distance less than 50 mm.