A microwave and microfluidic planar resonator for efficient and accurate complex permittivity characterization of aqueous solutions
Résumé
A microwave resonator is presented as a microfabricated sensor dedicated to liquid characterization with perspectives for chemistry and biology. The nanolitter range aqueous solution under investigation is located on top of the planar resonator thanks to a microfluidic channel compatible with a future lab-on-a-chip integration. The interaction between the electric field and the liquid translates into a predictable relationship between electrical characteristics of the resonator (resonant frequency and associated insertion loss) and the complex permittivity of the fluid (real and imaginary parts). A prototype of the resonator has been fabricated and evaluated with de-ionized water/ethanol mixtures, with ethanol volume fraction ranging from 0 to 20 %. Good agreement has been reached between theoretical and measured electrical parameters of the resonator. The discrepancy on the resonant frequency is estimated to 0.5 %, whereas the one on the associated transmission coefficient is lower than 1 %. This translates into a maximum relative error on the real and imaginary part of the predicted relative permittivity of less than 6.5 % and 4 % respectively, validating the principle of this accurate permittivity characterization methodology.
Domaines
Electromagnétisme
Origine : Fichiers produits par l'(les) auteur(s)
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