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Broadband Permittivity Measurements of Liquid and Biological Samples using Microfluidic Channels



James Booth, Jordi Mateu, Michael D. Janezic, James R. Baker-Jarvis, James A. Beall


We have developed an integrated microfluidic/microelectronic measurement platform in order to accurately measure the dielectric properties of sub-?L volumes of liquids at frequencies up to 40 GHz. We use on-wafer calibration techniques to obtain accurate S-parameter measurements of fluids and biological samples in solution contained within microfluidic structures directly integrated with patterned coplanar waveguide transmission lines. Our analysis yields the capacitance and conductance per unit length of our fluid-loaded transmission lines, and finite element simulations yield the relative permittivity as a continuous function of frequency up to 40 GHz. We demonstrate the technique with measurements of the complex permittivity of de-ionized water and methanol. Results for the frequency-dependent permittivity obtained in our microfluidic test structures show good agreement with bulk fluid measurements over a comparable frequency range. We expect this technique to be useful for rapid electromagnetic characterization of sub- microliter volumes of both liquids and biological samples in solution.
Proceedings Title
IEEE-MTT-S International Microwave Symposium Digest
Conference Dates
June 11-16, 2006
Conference Location
San Francisco, CA, USA
Conference Title
IEEE International Microwave Symposium


broadband dielectric response, dielectric spectroscopy, liquid permittivity, microfluidic channels


Booth, J. , Mateu, J. , Janezic, M. , Baker-Jarvis, J. and Beall, J. (2006), Broadband Permittivity Measurements of Liquid and Biological Samples using Microfluidic Channels, IEEE-MTT-S International Microwave Symposium Digest, San Francisco, CA, USA (Accessed June 13, 2024)


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Created June 10, 2006, Updated October 12, 2021