Hitachi‘s µ-chip (mu-chip) is designed to be small enough that it could be embedded in paper at the point of manufacture (see Hitachi Unveils Smallest RFID Chip). The tiny chip measures just 0.4 millimeter (0.02 inch) by 0.4 millimeter (0.02 inch) and has an antenna built into it. The chip operates at 2.45 GHz and can be read only from a very short distance. Because it is so small, it feels like a little bump in the paper that is almost undetectable.
Another option is to use chipless RFID systems. A company called Inkode makes aluminum fibers that can be embedded randomly in paper during the manufacturing process (see 1-Cent RFID Tags for Supermarkets). When the paper is hit with RF energy, the metal filings reflect back the radio waves in a unique pattern. Computers associate a specific pattern with a particular piece of paper. As such, the system can be used to authenticate goods.
If any of our readers are aware of other systems used for embedding RFID in paper, please post information below.
—Mark Roberti, Editor, RFID Journal
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