A 20-GHz Microwave Miniaturized Ring Resonator for nL Microfluidic Sensing Applications

In this article, a miniaturized microwave resonator is designed and fabricated. A loop-mode resonance is created when the permittivity difference between the two materials loaded in the two fluidic channels is sufficiently large. A highly concentrated electrical field is generated in a microfluidic channel loaded with deionized water to achieve high sensing spatial resolution within a sensing volume of 45 pL. On-wafer measurements are performed by keeping one channel unloaded as a reference while loading the other channel with different mixtures of isopropanol and deionized water. The acquired microwave-microfluidic measurements confirm that the proposed resonator can detect changes in the permittivity of the loaded liquid between the values of 3.2 and 42.4, making it a promising low-cost and label-free approach in applications requiring novel sensing techniques such as mixing monitoring and flow cytometry.

[1]  A. Kenworthy,et al.  Analyzing Single Giant Unilamellar Vesicles With a Slotline-Based RF Nanometer Sensor , 2016, IEEE Transactions on Microwave Theory and Techniques.

[2]  I. Ocket,et al.  Investigation of thermal effect caused by different input power of biosensor using a novel microwave and optical sensing system for biological liquids , 2017, 2017 First IEEE MTT-S International Microwave Bio Conference (IMBIOC).

[3]  Bart Nauwelaers,et al.  Hybrid Characterization of Nanolitre Dielectric Fluids in a Single Microfluidic Channel Up to 110 GHz , 2017, IEEE Transactions on Microwave Theory and Techniques.

[4]  D. Dubuc,et al.  A Microwave and Microfluidic Planar Resonator for Efficient and Accurate Complex Permittivity Characterization of Aqueous Solutions , 2013, IEEE Transactions on Microwave Theory and Techniques.

[5]  K. Foster,et al.  RF-field interactions with biological systems: Electrical properties and biophysical mechanisms , 1980, Proceedings of the IEEE.

[6]  Song Liu.  Microwave-Microfluidics: Sensor, Fluid Metrology, and Vector-Network-Analyzer Calibrations , 2016 .

[7]  M. Rols,et al.  Microwave Monitoring of Single Cell Monocytes Subjected to Electroporation , 2017, IEEE Transactions on Microwave Theory and Techniques.

[8]  S. Cerveny,et al.  Dielectric spectroscopy in the GHz region on fully hydrated zwitterionic amino acids. , 2012, Physical chemistry chemical physics : PCCP.

[9]  J. R. Claycomb,et al.  Low-frequency, low-field dielectric spectroscopy of living cell suspensions , 2004 .

[10]  Ali M. Niknejad,et al.  A 6.5/17.5-GHz dual-channel interferometer-based capacitive Sensor in 65-nm CMOS for high-speed flow cytometry , 2014, 2014 IEEE MTT-S International Microwave Symposium (IMS2014).

[11]  Michael D. Janezic,et al.  Quantitative Permittivity Measurements of Nanoliter Liquid Volumes in Microfluidic Channels to 40 GHz , 2010, IEEE Transactions on Instrumentation and Measurement.

[12]  P Lunkenheimer,et al.  Broadband dielectric spectroscopy on human blood. , 2011, Biochimica et biophysica acta.

[13]  G. Whitesides.  The origins and the future of microfluidics , 2006, Nature.

[14]  T. Fujii,et al.  Integrated Broadband Microwave and Microfluidic Sensor Dedicated to Bioengineering , 2009, IEEE Transactions on Microwave Theory and Techniques.