High sensitivity microwave characterization of organic molecule solutions of nanoliter volume

A microwave resonator composed of a sapphire cylinder and a quartz plate with a 400 nl cavity was developed for the determination of the complex permittivity of liquids at 10 GHz. This sensor was calibrated over a wide range of values for real and imaginary parts of permittivity. The measured resonator losses induced by the liquid were found to be proportional to the dipole relaxation time of the liquid molecules, as predicted by perturbation theory. Our analysis of weight concentration and temperature dependence of the measured inverse quality factor revealed a sensitivity of about 0.1% for aqueous solutions of glucose.

[1]  Jerzy Krupka,et al.  Dielectric properties of single crystals of Al/sub 2/O/sub 3/, LaAlO/sub 3/, NdGaO/sub 3/, SrTiO/sub 3/, and MgO at cryogenic temperatures , 1994 .

[2]  Ashim K. Datta,et al.  Handbook of Microwave Technology for Food Application , 2001 .

[3]  J. Barthel,et al.  The dielectric relaxation of water between 0°C and 35°C , 1999 .

[4]  Jinxing Liang,et al.  Wet etched high aspect ratio microstructures on quartz for MEMS applications , 2007 .

[5]  Udo Kaatze,et al.  Molecular Dynamics of Carbohydrate Aqueous Solutions. Dielectric Relaxation as a Function of Glucose and Fructose Concentration , 2001 .

[6]  Kiejin Lee,et al.  Microwave dielectric resonator biosensor for aqueous glucose solution. , 2008, The Review of scientific instruments.

[7]  U. Kaatze,et al.  Water−Ethanol Mixtures at Different Compositions and Temperatures. A Dieletric Relaxation Study , 2000 .

[8]  Andreas Offenhäusser,et al.  Nanoliter liquid characterization by open whispering-gallery mode dielectric resonators at millimeter wave frequencies , 2008 .

[9]  Jun Xiao,et al.  Noninvasive blood glucose measurement system based on three wavelengths in near-infrared region , 2007, International Conference on Photonics and Imaging in Biology and Medicine.

[10]  D. Kajfex,et al.  Dielectric Resonators , 1986 .

[11]  M M Gebhard,et al.  The complex dielectric spectrum of heart tissue during ischemia. , 2002, Bioelectrochemistry.

[12]  A. Stogryn,et al.  Equations for Calculating the Dielectric Constant of Saline Water (Correspondence) , 1971 .

[13]  J. Krupka,et al.  Room temperature measurement of the anisotropic loss tangent of sapphire using the whispering gallery mode technique , 2006, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.