Hitachi's Tiny RFID Chips

paltemalte writes "Hitachi has just come out with a new crop of RFID tags, measuring only 1/20 of a millimeter square. That's 1/8 the size (in linear dimension) of Hitachi's currently shipping mu-chips, which are 0.4 mm square. The new chip's width is slightly smaller than a human hair. These chips could put an end to shoplifting forever, but they could also be used by a governments or other entities to 'dust' crowds or areas, easily tagging anyone present without their knowledge or consent. Will someone come up with a surefire way of neutralizing chips that may be on your body or in your clothing?" Hard to pin down a source on this. The article cites another blog, which points to an article in Japanese.

What they didn't tell you

[JesseL]

Most RFID chips still have to be attached to a much larger coil antenna to make a tag that will actually work.

Small tags have inherent limitations

[Anonymous Coward]

These tags are 1/20th mm square, correct? This means they are 1e-3/20 m = 5e-5m across. This corresponds to a frequency of 6 THz or for a quarter-wave antenna something like 6/4 THz = 1.5 THz. This is a very high frequency and not the easiest to make with existing technology (especially at significant power levels). This means that querying tags of this size is probably only feasible at short range using a beam that is directed at the tag as opposed to just looking in a vague region of space. Other companies have made optically addressed tags that push this direction even further but with even worse limitations. Also, at ~1 THz the attenuation due to dielectrics (or especially water) is very high and this limits the distance over which one can practically probe the chip.

Re:Something to worry about... but maybe not so mu

[sunwukong]

Hitachi's current product, the Mu-chip [hitachi-eu.com], has a supposed reading range of 400mm with a 54mm antenna [hitachi-eu.com].

Dunno what the proposed range and antenna requirements for the new chip will be.

EASY to pin down a source.

[1u3hr]

The summary says: "Hard to pin down a source on this. The article cites another blog, which points to an article in Japanese."

RTFA FFS. It has a link to Hitachi [hitachi.co.jp], in English:

The mu-chip is Hitachi's response to resolving some of the issues associated with conventional RFID technology. The mu-hip uses the frequency of 2.45GHz. It has a 128-bit ROM for storing the ID with no write-read and no anti-collision capabilities. Its unique ID numbers can be used to individually identify trillions of trillions of objects with no duplication. Moreover with a size of 0.4mm square, the mu-chip is small enough to be attached to a variety of minute objects including embedding in paper.

Re:Small tags have inherent limitations

[Kadin2048]

This is just the transciever chip; it has to have an external antenna. Elsewhere, people have discussed their current chip offerings, which have antennas in the ~50mm range. Generally they print them out in the shape of a labyrinth-like square, to take up less space, but it still increases the size pretty dramatically.

I suspect if you took the same antenna and made it into a 3d cube instead of a 2d concentric spiral, you'd probably end up with something pretty small ... still, not "dust" size.

Re:Something to worry about... but maybe not so mu

[Djupblue]

The reading distance is not so much limited by reader sensitivity as the amount of rf-power received by the chip. The chip has to receive enough power to operate, albeit very little. Then the chip creates a modulated reflection, that means that the more power you transmit the more power you get back. The specified reading range is not a hard limit, you can get a lot longer distance if you use a reader that put out more power than the spec states. We read rfid chips at up to about 10 meters in optimal conditions with compliant readers.

Re:Covered with Hair?

[paltemalte]

Again the slashdot editor obfuscated my post. I wrote 'the WIDTH of the RFID chip is less than the WIDTH of a human hair'. RTFA and see the images for yourself. They could easily be 'dusted' out.

Re:Something to worry about... but maybe not so mu

[kirun]

Why would they bother RFIDing the crowd when they could just spray them with Smart Water [smartwater.com]? The patrols with their hi-tech scanners could be replaced with ones wielding UV lamps.

Re:Fighting back with RFID readers

[Richy_T]

No longer affiliated with this place but they have an affordable kit and are helpful with questions intersoft-us

Re:What they didn't tell you

[sysopd]

Most RFID chips still have to be attached to a much larger coil antenna to make a tag that will actually work.

The "new" RFID innovation for embedding in clothing etc is conductive thread antennae. The antenna is woven into the clothing or item and disguises as an ordinary thread. To be less conspicuous the thread can be woven into the label or a seam.

Philips patent for a flexible fabric antenna [freepatentsonline.com].