Batteryless RFID sensor chip sends measured data out of aqueous solutions

13th November 2017. At the MEDCIA trade fair in Düsseldorf, Germany, IMMS presents via live-demo a passive RFID microelectronic chip with remote power supply. Placed into aqueous solutions, the chip measures temperature data which is captured and processed by an RFID reader unit. With this energy-efficient chip developed by IMMS, values are being measured and digitised with a power consumption of very few microwatts (approximately 3.5 microwatt). This would facilitate the use of a sensor operable without interruption for at least a 10-year period from a mignon battery with a typical capacity of 1000 mAh. Thanks to this ultra-low power consumption a battery is dispensable: an RFID reader unit generates an electromagnetic field which is sufficient to supply the passive RFID chip with power and to record and send data through containers and liquids over distances of up to four centimetres.

The development is a result of the ADMONT European Union joint project which sees IMMS doing research and development on the design of intelligent in-vitro diagnostic und bioanalytical sensor and actuator systems and which will run until 2019. The RFID-Chip combines high accuracy, energy-efficient operation and cost efficiency. The new digital RFID-coupled temperature sensor acquires values in the large measuring range from –40 °C to 125 °C with an accuracy of +/–0,5 °C. To reach a power consumption of only 3.5 microwatt, IMMS eliminated analog-to-digital converters which consume much energy. As a substitute, IMMS implemented a time-coded signal processing which allows the conversion of temperature values into timing signals. This digital information can be handled with minimised energy consumption. For a low-cost solution IMMS harnessed off-the-shelf, reasonably priced CMOS technology and developed a single-chip solution with integrated sensors and with embedded electronic signal processing. This chip does not need any further components besides the RFID antenna.

The batteryless principle for RFID sensors which is introduced at the MEDICA is currently being transferred by IMMS to other measurands to lay the foundation for various applications in bioanalysis and beyond.