Miniaturization

RFID is the technology which makes it easy to conceal or incorporate them in other items. For example, in 2009 researchers at Bristol University successfully glued RFID microtransponders to live ants in order to study their behavior.^[7] This trend towards increasingly miniaturized RFID is likely to continue as technology advances. However, the ability to read at distance is limited by the inverse-square law.

Hitachi holds the record for the smallest RFID chip, at 0.05mm x 0.05mm. The Mu chip tags are 64 times smaller than the new RFID tags.^[8] Manufacture is enabled by using the Silicon-on-Insulator (SOI) process. These "dust" sized chips can store 38-digit numbers using 128-bit Read Only Memory (ROM).^[9] A major challenge is the attachment of the antennas, thus limiting read range to only millimeters.

Potential alternatives to the radio frequencies (0.125–0.1342, 0.140–0.1485, 13.56, and 840–960 MHz) used are seen in optical RFID (or OPID) at 333 THz (900 nm), 380 THz (788 nm), 750 THz (400 nm).^[10] The awkward antennas of RFID can be replaced with photovoltaic components and IR-LEDs on the ICs!