Method for Estimating Complex Permittivity Based on Measuring Effective Permittivity of Dielectric Mixtures in Radio Frequency Band

Hidetoshi EBARA  Kensuke TANI  Teruo ONISHI  Shinji UEBAYASHI  Osamu HASHIMOTO  

IEICE TRANSACTIONS on Communications   Vol.E88-B   No.8   pp.3269-3274
Publication Date: 2005/08/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.8.3269
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section of 2004 International Symposium on Electromagnetic Compatibility)
Category: Biological Effects
dielectric measurement,  coaxial line,  phospholipid,  effective permittivity,  mixing formula,  

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This paper proposes a method for estimating the complex permittivity of a small quantity of a sample such as a biological membrane. The feature of this method is that a material with an unknown complex permittivity is mixed with a material with a known complex permittivity in a number of volume ratios. The unknown complex permittivity is estimated by measuring the effective permittivity of the mixtures and by using the mixing formula, which is applied to the composite material. The validity of this estimation method is evaluated using a phospholipid, which is the primary constituent of a biological membrane, in the frequency range from 0.8 GHz to 6 GHz. We confirm that the measured effective permittivity of the phospholipid mixtures, which comprise the phospholipid and Ringer's solution in a number of volume ratios, corresponds to that of the Lichtenecker formula. Additionally, by preparing a number of samples with varying volume ratios the estimation error can be decreased. This estimation method is considered to be effective in the measurement of the complex permittivity for a biological membrane.