同轴线测量材料电磁参数的改进NRW传输/反射法

研究了传统的NRW传输/反射法的半波谐振和多值性问题,给出了同轴NRW传输/反射法更加完善的改进方法和相应的不确定度分析方法.使用自动矢量网络分析仪和7Φmm同轴线,在100 MHz-6 GHz频率范围内对空气和Teflon进行了测量.依据改进的方法计算的复介电常数值与参考值在整个频率范围内符合得很好,证明了该改进方法能够有效地解决半波谐振和多值性问题,且计算结果与试样在同轴线中的位置以及同轴线的长度无关.

Improved NRW Transmission/Reflection Method for the Determination of Electromagnetic Parameters of Materials with Coaxial Line

After discussing the half-wavelength divergence and multi-roots problems of traditional NRW trans-mission/reflection method, a better improved method using coaxial line and relevant uncertainty analysis are presented.Air and Teflon had been tested using a vector network analyzer and Φ7mm coaxial with the respectively from 100 MHz to 6 GHz. The measurement results obtained by the improved method agree with the reference values of the materials under test very well at all frequencies. The agreements prove that the improved method has greater effect in solving the half-wavelength divergence and multi-roots problems and is independent of the coaxial line' s length and the position of sample under test in the coaxial line.