Department of Microelectronics
Faculty of Electrical Engineering, Mathematics, and Computer Science

Integrated Near Field sensOrs for high Resolution MicrowavE spectRoscopy

Publications

  1. Miniaturized Broadband Microwave Permittivity Sensing for Biomedical Applications
    G. Vlachogiannakis; Z. Hu; H. T. Shivamurthy; A. Neto; M. A. P. Pertijs; M. Spirito; L. C. N. de Vreede;
    IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology,
    Volume 3, Issue 1, pp. 48--55, March 2019. DOI: 10.1109/JERM.2018.2882564
    Abstract: ... A compact sensing pixel for the determination of the localized complex permittivity at microwave frequencies is proposed. Implemented in the 40-nm CMOS, the architecture comprises a square patch, interfaced to the material-under-test sample, that provides permittivity-dependent admittance. The patch admittance is read out by embedding the patch in a double-balanced, RF-driven Wheatstone bridge. The bridge is cascaded by a linear, low-intermediate frequency switching downconversion mixer, and is driven by a square wave that allows simultaneous characterization of multiple harmonics, thus increasing measurement speed and extending the frequency range of operation. In order to allow complex permittivity measurement, a calibration procedure has been developed for the sensor. Measurement results of liquids show good agreement with theoretical values, and the measured relative permittivity resolution is better than 0.3 over a 0.1-10-GHz range. The proposed implementation features a measurement speed of 1 ms and occupies an active area of 0.15x0.3 mm², allowing for future compact arrays of multiple sensors that facilitate 2-D dielectric imaging based on permittivity contrast.

  2. A 40-nm CMOS Complex Permittivity Sensing Pixel for Material Characterization at Microwave Frequencies
    G. Vlachogiannakis; M. A. P. Pertijs; M. Spirito; L. C. N. de Vreede;
    IEEE Transactions on Microwave Theory and Techniques,
    Volume 66, Issue 3, pp. 1619-1634, March 2018. DOI: 10.1109/tmtt.2017.2753228
    Abstract: ... A compact sensing pixel for the determination of the localized complex permittivity at microwave frequencies is proposed. Implemented in the 40-nm CMOS, the architecture comprises a square patch, interfaced to the material-under-test sample, that provides permittivity-dependent admittance. The patch admittance is read out by embedding the patch in a double-balanced, RF-driven Wheatstone bridge. The bridge is cascaded by a linear, low-intermediate frequency switching downconversion mixer, and is driven by a square wave that allows simultaneous characterization of multiple harmonics, thus increasing measurement speed and extending the frequency range of operation. In order to allow complex permittivity measurement, a calibration procedure has been developed for the sensor. Measurement results of liquids show good agreement with theoretical values, and the measured relative permittivity resolution is better than 0.3 over a 0.1-10-GHz range. The proposed implementation features a measurement speed of 1 ms and occupies an active area of 0.15x0.3 mm², allowing for future compact arrays of multiple sensors that facilitate 2-D dielectric imaging based on permittivity contrast.

  3. A 5x5 Microwave Permittivity Sensor Matrix in 0.14-μm CMOS
    Z. Hu; G. Vlachogiannakis; M. A. P. Pertijs; L. C. N. de Vreede; M. Spirito;
    In Proc. IEEE MTT-S International Microwave Symposium (IMS),
    6 2018. DOI: 10.1109/MWSYM.2018.8439438

  4. A Compact Energy Efficient CMOS Permittivity Sensor Based on Multi-Harmonic Downconversion and Tunable Impedance Bridge
    G. Vlachogiannakis; Z. Hu; H. T. Shivamurthy; A. Neto; M. A. P. Pertijs; L. C. N. de Vreede; M. Spirito;
    In Int. Microwave Biomedical Conference (IMBioC),
    pp. 1--3, June 2018. DOI: 10.1109/IMBIOC.2018.8428950
    Abstract: ... This paper presents a 0.15×0.3 mm2 complex permittivity sensor integrated in a 40-nm CMOS node. A single-ended patch, employed as a near-field sensing element, is integrated with a double-balanced, fully-differential tunable impedance bridge that is driven by a square RF pulse. The multi-harmonic, intermediate-frequency down-conversion architecture achieves a compact form factor and fast multi-frequency readout. Measurement results show good agreement with theoretical values and the measured relative permittivity variation remains below 0.3 over a 0.1-10 GHz range at a 1-ms measurement time. The energy efficiency resulting from the fast measurement time and the record-small active area allows integration in battery-operated wearables.

  5. A 40-nm CMOS permittivity sensor for chemical/biological material characterization at RF/microwave frequencies
    G. Vlachogiannakis; M. Spirito; M. A. P. Pertijs; L. C. N. de Vreede;
    In Proc. IEEE MTT-S International Microwave Symposium (IMS),
    IEEE, pp. 1‒4, May 2016. DOI: 10.1109/mwsym.2016.7540260

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