Who makes the tiniest tag?
There are different types of RFID tags, so there are different types of tags that could qualify as the smallest. Electronic component manufacturer Murata Manufacturing Co. offer the smallest high-frequency (HF) tag available on the market. It measures 3.2 millimeters (0.13 inch) in width and length and 0.7 millimeter (0.03 inch) in thickness. Murata's transponder has a ceramic substrate enclosing a layered circuit board and an antenna (see Murata Mass-Produces 'World's Smallest HF Tag').
Hitachi Chemical sells the smallest EPC Gen 2 passive ultrahigh-frequency (UHF) RFID tag. It measures just 2.5 millimeters (0.098 inch) square and 0.3 millimeter (0.012 inch) thick. Consisting of an Impinj Monza 5 chip and an antenna embedded in epoxy resin, the Ultra-Small Package tag is designed to be durable enough that it could be applied via injection molding or incorporated into printed circuit boards. This means the tag could be built into a circuit board or a semiconductor's packaging and sustain the temperatures typically used during manufacturing processes—as high as 260 degrees Celsius, or 500 degrees Fahrenheit (see Hitachi Chemical Markets Tiny UHF Tag).
There are also passive low-frequency (LF) transponders in glass ampoules that measure 2 millimeters in diameter and 12 millimeters in length. These are typically used for injecting into animals for identification.
Smaller tags have a shorter read range, since they cannot capture as much energy from a reader antenna. French RFID solutions provider Tagsys RFID and Impinj have gotten around this issue by creating a small tag that can be attached to a metal object and use that object as its antenna. The AK Tag measures 10 millimeters by 12 millimeters (0.4 inch by 0.5 inch) as an inlay, and 20 millimeters square (0.8 inch square) when converted into an RFID label. Despite its small size, the tag provides read ranges similar to those of much larger tags, by harvesting RF energy from the goods or packaging to which it is attached. The AK Tag can be placed over or attached to a metal object that serves as a secondary antenna to boost read distance (see Tagsys Releases Two Small Long-Range Passive UHF Tags).
—Mark Roberti, Founder and Editor, RFID Journal