Skip to main content

A Passive UHF RFID Dielectric Sensor for Aqueous Electrolytes

Hillier, Aaron, Makarovaite, V., Gourlay, Campbell W., Holder, Simon J., Batchelor, John C. (2019) A Passive UHF RFID Dielectric Sensor for Aqueous Electrolytes. IEEE Sensors Journal, 19 (11). pp. 4299-4307. ISSN 1530-437X. E-ISSN 1558-1748. (doi:10.1109/JSEN.2019.2896481)


The one step modification of a commercial RFID sensing tag is demonstrated using polydimethylsiloxane based thin film chemistry to construct reusable passive RFID sensors for changes in the dielectric properties of electrolyte solutions as a function of concentration. The effects of PDMS film thickness were characterized as a function of RFID sensor code value. The output sensor code of the RFMicron RFM2100-AER wireless flexible moisture sensor (taken between 800-860 MHz) was compared to readings taken when the tag was dry and when the tag had a water deposition on the sensor area. The effect of the direct application of liquid water to the tag was to alter the capacitance presented to the integrated chip which auto-tunes to correct for the reactance. By varying the thickness of the PDMS film between the interdigitated sensor and deposited liquid, the sensitivity of the tag to a high dielectric medium could be controlled. Aqueous salt solutions were tested on a 500 m thickness film. It was found that the sensing platform could be used as a means of measuring the concentration of various salt solutions within the range 0-2M, and in turn could be used as a passive UHF RFID dielectric measuring tool. The measurement capability of the platform was subsequently demonstrated using a reduced frequency range (845-865 MHz).

Item Type: Article
DOI/Identification number: 10.1109/JSEN.2019.2896481
Projects: [UNSPECIFIED] Foresight Fellowship in Manufacturing: Defining and Fabricating New Passive Bio-Sensing Wireless Tag Technologies.
Uncontrolled keywords: Radio Frequency Identification, RFID tags, chemical sensor, aqueous electrolyte.
Subjects: Q Science > QD Chemistry
T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800 Electronics (see also: telecommunications) > TK7871.6 Antennas and waveguides > TK7871.67.M53 Microwave antennas
Divisions: Faculties > Sciences > School of Biosciences
Faculties > Sciences > School of Engineering and Digital Arts > Broadband & Wireless Communications
Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: John Batchelor
Date Deposited: 08 Apr 2019 08:56 UTC
Last Modified: 09 Jul 2019 09:03 UTC
Resource URI: (The current URI for this page, for reference purposes)
Gourlay, Campbell W.:
Holder, Simon J.:
Batchelor, John C.:
  • Depositors only (login required):


Downloads per month over past year