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MWagih_uFluid_TripleStub_Sensor.pdf (5.5 MB)

Scalable All-Printed Microwave Microfluidic Sensor for Multi-Liquid Characterization based on a Stub-Loaded Microstrip Line

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posted on 02.08.2021, 03:52 by Mahmoud WagihMahmoud Wagih, Junjie Shi
Microwave microfluidic sensors are typically designed with a channel in vicinity of a resonator's fringing electric (E)-fields, to characterize the material properties of a single fluid. This paper leverages hybrid 3D and dispenser printing to realize a scalable microfluidic sensor utilizing the parallel-plate capacitance of an open-ended microstrip stub, enabling, for the first time, a tunable sensitivity. A stub-loaded microstrip line is then proposed for characterizing multiple microfluidic samples simultaneously using a simple two-port multi-band resonator. The physical constrains which limit the scalability of the proposed sensors have been analyzed analytically and numerically, prior to implementing a three-channel triple-band sensor. The microfluidic channels have been fabricated using stereolithography 3D printing with the microstrip line directly dispenser printed on a conformable polyimide substrate. To accommodate varying channel thicknesses, a tapered microstrip line is proposed to maintain the impedance matching. The fabricated sensor is characterized using binary water-IPA mixtures to evaluate its sensitivity, comparing favorably with reported 3D-printed sensors. The proposed sensor achieves over 90% accuracy in determining the real permittivity following a simple water-based calibration across the different channels, for samples with 16 oC temperature sensitivity across all channels.

Funding

Engineering and Physical Sciences Research Council (EPSRC)

History

Email Address of Submitting Author

mahm1g15@ecs.soton.ac.uk

ORCID of Submitting Author

https://orcid.org/0000-0002-7806-4333

Submitting Author's Institution

University of Southampton

Submitting Author's Country

United Kingdom