基于微带谐振法的介电常数无损伤测量

为了能够简便且无损伤地测量介质的介电常数,介绍了一种基于微带谐振法的介电常数无损伤测量方法,测量装置采用四分之一波长型阶跃阻抗谐振器(stepped impedance resonator,SIR)以及背面缝隙耦合的馈电结构,使得测量装置不仅尺寸小巧而且易于贴近待测介质表面进行非破坏性测量.待测介质的介电常数由待测介质的厚度和测量前后谐振频率的变化决定,三者的函数关系式由三维电磁仿真以及三维数据拟合获得.此外,设计并制作了一款谐振频率在2 GHz频段的实物装置,实测了6种样品的介电常数,测量结果与安捷伦E4991A测试仪的测量值进行比较.根据实测比对,该测量装置的相对测量精度在±6％.最后,仿真研究了接触面缝隙带来的测量误差,并给出了相应的参考曲线.

Nondestructive measurement of permittivity based on microstrip resonance method

In order to measure the permittivity of medium simply and non-invasively, This paper introduces a kind of non-destructive measurement method of permittivity based on microstrip resonance method. The measuring device adopts quarter-wave stepped impedance resonator (SIR) and feed structure of slot coupling on the back, so that the measuring device is small-sized and can easily get close to the surface of medium to do non-destructive measurement. Permittivity of the medium under test is determined by thickness of the medium and change of resonant frequency before and after the test, and the function equation of the three is obtained by three-dimensional electromagnetic simulation and three-dimensional data fitting. Besides, A material device with 2GHz frequency band is produced and the permittivity of 6 kinds of samples are measured. According to the measurement and comparing with the measured value obtained by Agilent E4991A tester, the device can attain relative accuracy within ±6%. Finally, simulation study for measuring error due to the contact surface crack is discussed and the corresponding reference curve is provided.