SAN FRANCISCO — A pair of papers presented here Tuesday (Feb. 10) at the IEEE's International Solid State Circuits Conference described breakthroughs in the field of organic electronics for RFID applications.
German printed electronics house PolyIC GmbH claims to have created the first working 4-bit organic CMOS transponder for a carrier frequency of 13.56 MHz, according to a paper presented. The prototype transponder was created as a proof of concept and has yet to be optimized in any way, said Robert Blache, one of the paper's authors.
According to Blache, a number of groups have demonstrated prototypes of p-type organic tags working at 13.56 MHz. But the PolyIC prototype is believed to be the first demonstration of an RFID transponder, he said.
Organic CMOS devices, made using carbon-based materials like common plastic, are seen as a promising technology because—unlike silicon-based devices—they can be printed on thin, large and flexible films. However, organic electronics have technical limitations compared to silicon-based devices, including speed and accuracy issues.
Organic CMOS devices are seen as particularly promising for RFID applications because they can be bent and could be printed on product packaging, eventually replacing the ubiquitous barcodes but carrying much more information.
Organic circuits also typically degrade over time in storage, according to Blache. However, PolyIC's prototype continued to work at 13.56 MHz even after 15 months of storage, considered adequate shelf life for organic electronics without encapsulation, he said.
"As you can see," Blache said, "the shelf life is sufficient for simple applications."
The PolyIC prototype devices are fabricated on flexible polyester substrate roughly 250-um thick, according to the paper presented by Blache. Besides the electrodes, all layers of the device consist of soluble organic molecules deposited by spin coating on a substrate, according to the paper. The device has a clock frequency of 196Hz at -20V supply voltage.
Earlier Tuesday, a paper by engineers from Belgian nanoelectronics research institute IMEC and elsewhere described an organic RFIG containing 128 bits of data, similar to low-end silicon RFIDs. The device incorporates Manchester encoding and uses a basic anti-collision protocol to enable the readout of multiple tags at once, according to the paper.
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