PERMITTIVITY MEASUREMENT OF THIN DIELECTRIC MATERIALS FROM REFLECTION-ONLY MEASUREMENTS USING ONE-PORT VECTOR NETWORK ANALYZERS

We have proposed a simple waveguide method for complex permittivity determination of dielectric materials which are not completely filling the entire sample holder. The method reconstructs the permittivity from measured reflection-only scattering parameters by a one-port vector network analyzer of two configurations of the sample holder. It not only eliminates the necessity of any knowledge of the location of the shifted sample inside its holder but also decreases measurement errors occurring with the presence of undesired air gaps, which seriously affect the measurement accuracy of transmission-only measurements, present between the sample and holder walls. Furthermore, there construction of permittivity can be realized by anyone-port vector network analyzer, which is less expensive than their two-port counter parts. Therefore, the proposed method is cost-effective. We have analyzed the accuracy of the proposed method and noted a good compromise between the reference data and measured values of permittivities of low-loss polyvinyl-chloride and polytetrafluoro.ethylene samples (less than 8 percent for dielectric constant and less than 15 percent for loss tangent values).