Organic RFID tags to zap bar codes

Researchers from European R&D institution Holst Centre said their 64bit, inductively coupled, passive RFID tag achieved a record 780bit/s data readout.

In a presentation at the International Solid-State Circuits Conference, the researchers said the performance over a distance of 10cm approaches the requirements for tagging products and other items. The tag represents a fivefold increase in bit-rate performance over plastic RFIDs. The achievement could pave way for low-cost, high-volume RFID tags to replace bar codes.


The foil used for the transponder chip (top) and the fully flexible, 64bit organic RFID tag (bottom).

The 64bit RFID consists of a low-cost inductive antenna, capacitor, plastic rectifier and plastic circuit, all on foil. The antenna operates at 13.56MHz and powers up the organic rectifier with an AC voltage at that frequency. From that voltage, the rectifier generates a DC supply voltage for the 64bit organic transponder chip. The chip drives the modulation transistor between on/off states with a 64bit code sequence.

Organic electronics
The foil used for the transponder chip was processed with organic electronic technology provided by Holst Centre partner Polymer Vision. Organic vertical diodes are used in rectifiers because they outperform organic transistors at frequencies at and above 13.56MHz. At an RF magnetic field strength of 1.26A/m, the rectifier generates an internal transponder supply voltage of 14V. At that voltage, the 64bit code is read out at 787bit/s. The 64bit transponder chip uses organic bottom-gate, p-type, pentacene thin-film transistors from a soluble precursor route. It includes about 400 transistors, making it significantly smaller than previous designs.

The Holst Centre was founded in 2005 by Belgian research center IMEC and its Dutch counterpart, TNO. It focuses on wireless microsystems and systems-in-foil.

- Nicolas Mokhoff
EE Times