The RFID Journal says that CrossID, an Israeli startup, has developed an RFID system that can be printed using an inkjet printer.

CrossID, an Israeli startup founded by two engineers formerly at the telecommunications equipment provider RAD Group, has developed an innovative, chipless RFID system that can protect sensitive documents, such as intelligence agency reports, financial securities and banknotes. The technology could also be used to create a “hands-free” bar code.

The system uses “nanometric” materials—tiny particles of chemicals with varying degrees of magnetism—that resonate when bombarded with electromagnetic waves from a reader. Each chemical emits its own distinct radio frequency, or “note,” that is picked up by the reader, and all the notes emitted by a specific mix of different chemicals are then interpreted as a binary number. Since the system uses up to 70 different chemicals, each chemical is assigned its own position in a 70-digit binary number.

For example, if the chemicals A, B, C and D were assigned to the first, second, third and fourth positions in the 70-digit number, then a mixture consisting of A and C would represent the binary number 1010 followed by 66 zeros. CrossID is testing readers that operate at three to 10 GHz, which is higher than the frequencies commonly used by wireless LANs and handheld computers, although the company has not made a final determination on what frequency the readers will use.

More here.