Study on complex permittivity of materials with temperature change by microwave heating

To measure the temperature dependent complex permittivity for dielectric materials, a TM₀₁₀ mode of cylindrical cavity resonator at a frequency of 2.45 GHz has been designed. In the measurement, the output power of vector network analyzer is gained with RF power amplifier to heat materials while simultaneously obtaining complex permittivity by measuring transmission coefficient. The experimental results are examined, and the measuring accuracy of complex permittivity by the perturbation method is discussed comparing rigorous analysis for TM₀₁₀ mode cylindrical cavity resonator. From the results, it is found that the error of the result for relative dielectric constant became 1.5 % or less.