Simplification of Liquid Dielectric Property Evaluation Based on Comparison with Reference Materials and Electromagnetic Analysis Using the Cut-Off Waveguide Reflection Method


IEICE TRANSACTIONS on Electronics   Vol.E100-C   No.10   pp.908-917
Publication Date: 2017/10/01
Online ISSN: 1745-1353
Type of Manuscript: Special Section PAPER (Special Section on Microwave and Millimeter-Wave Technology)
dielectric measurement,  liquid,  coaxial line,  mode-matching technique,  electromagnetic analysis,  

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In this study, expressions were compared with reference material using the coaxial feed-type open-ended cut-off circular waveguide reflection method to support simple and instantaneous evaluation of dielectric constants in small amounts of scarce liquids over a broad frequency range. S11 values were determined via electromagnetic analysis for individual jig structure conditions and dielectric property values without actual S11 measurement under the condition that the tip of the measurement jig with open and short-ended conditions and with the test material inserted. Next, information on the relationships linking jig structure, dielectric properties and S11 properties was stored on a database to simplify the procedure and improve accuracy in reference material evaluation. The accuracy of the estimation formula was first theoretically verified for cases in which values indicating the dielectric properties of the reference material and the actual material differed significantly to verify the effectiveness of the proposed method. The results indicated that dielectric property values for various liquids measured at 0.5 and 1.0GHz using the proposed method corresponded closely to those obtained using the method previously proposed by the authors. The effectiveness of the proposed method was evaluated by determining the dielectric properties of certain liquids at octave-range continuous frequencies between 0.5 and 1.0GHz based on interpolation from limited data of several frequencies. The results indicated that the approach enables quicker and easier measurement to establish the complex permittivity of liquids over a broad frequency range than the previous method.