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Broadband Permittivity of Liquids Extracted from Transmission Line Measurements of Microfluidic Channels



Jordi Mateu, Nate Orloff, Matthew Rinehart, James Booth


We present a semi-analytical procedure to extract the permittivity of fluids from measurements in our microfluidic-microelectronic platform. This platform consists of broadband coplanar waveguide transmission lines with embedded microfluidic channels on top for electromagnetic characterization of micorliter samples. On-wafer calibration techniques are used to obtain the S-parameters of the whole structure(transmission line and microfluid channel) up to 40 GHz. Using microwave network analysis theory we isolate the microfluidic channel response. We approach the microfluid channel as a distributed transmission line segment and as a single RLCG elemental segment. Both approaches analytically yield the circuit capacitance CF and conductance GF per unit length of the microfluid channel segment. A finite element electromagnetic simulator is then used to obtain the permittivity of the fluid as a continuous function of frequency. We applied this technique to extract the permittivity of several liquids. Here, we present results on polystyrene latex beads solution, from 100 MHz to 40 GHz.
Conference Dates
June 3-8, 2007
Conference Location
Honolulu, HI, US
Conference Title
Microwave Symposium, 2007. IEEE/MTT-S International


Coplanar waveguides, Microfluid measurements, Permittivity Measurements


Mateu, J. , Orloff, N. , Rinehart, M. and Booth, J. (2007), Broadband Permittivity of Liquids Extracted from Transmission Line Measurements of Microfluidic Channels, Microwave Symposium, 2007. IEEE/MTT-S International, Honolulu, HI, US, [online],, (Accessed February 29, 2024)
Created June 2, 2007, Updated October 12, 2021