Full-Wave Modal Analysis of a Novel Dielectrometer for Accurate Measurement of Complex Permittivity of High-Loss Liquids at Microwave Frequencies

A novel dielectrometer to measure the complex permittivity of high-loss liquids is presented. The geometry consists of a reentrant cavity with insertion holes, where the holder filled with liquid can be introduced readily. Radii of the insertion holes are large enough for a convenient pouring of the liquid. The electromagnetic analysis has been performed by a mixed mode-matching and circuit technique with the purpose of taking the high accuracy and fast convergence of the mode-matching and the flexibility and versatility of the circuit method. The convergence of the method is studied, and a procedure to estimate the result for an infinite number of modes is proposed. A calibration procedure is presented to minimize the error introduced by the numerical method. Mode charts are shown to analyze the behavior of resonant parameters for every mode. Some reference liquids are measured at different resonant frequencies, and the results are compared with those provided by other models of the literature.