One-port CSRR Structure for Dielectric Characterization of Lossy Materials

In this study, a one-port structure developed around a complementary split ring resonator (CSRR) is presented for the dielectric characterization of high-loss materials. A novel high-quality method is proposed based on impedance matching of the CSRR structure. Impedance matching was achieved by tuning the length of the transmission line between the CSRR cell and an open circuit. In this work, the fabricated device was tested using various concentrations of water-ethanol mixtures. Finally, the complex permittivity was extracted by determining the input impedance of the device at the frequency at which the minimum $\vert S_{11}\vert$ occurs in the frequency range from 2.175 GHz to 2.225 GHz. The results show excellent agreement with the complex permittivity obtained using a commercially available dielectric probe set.