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, interme-diate-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.

Original languageEnglish
Title of host publication2018 IEEE International Microwave Biomedical Conference (IMBioC)
Number of pages3
ISBN (Electronic)978-1-5386-5918-2
ISBN (Print)978-1-5386-5919-9
Publication statusPublished - 2018
Event2018 IEEE/MTT-S International Microwave Biomedical Conference, IMBioc 2018 - Philadelphia, United States
Duration: 14 Jun 201815 Jun 2018


Conference2018 IEEE/MTT-S International Microwave Biomedical Conference, IMBioc 2018
CountryUnited States

    Research areas

  • Bridge circuits, Chemical and biological sensors, Microwave sensors, Near field, Permittivity, Sensitivity, Wearable sensors

ID: 50327164