Measurement of dielectric constant of waxes at different temperatures using split ring resonator structure

Dielectric constant variation with temperature for different wax samples is analysed with the help of split ring resonators (SRRs). The method employs a simple extraction procedure to obtain the unknown permittivity values from a calibration curve drawn between relative permittivity of standard samples and resonant frequency of SRR with each of the samples placed above it. The wax sample is placed on the SRR surface and its transmission characteristics are analysed using a vector network analyser (VNA) with its transmitting and receiving probes placed on either side of the SRR - sample system. The temperature is gradually increased from room temperature to 60°C with the help of a hot metal plate placed near the SRR. The dielectric constant of wax sample in contact with the SRR surface varies with the temperature, which in turn changes the capacitance of the SRR, resulting in a shift in its resonant frequency. The method has its advantages like simple experimental setup, direct measurement and ease of sample preparation.