Kathy posted an excellent Noxious Rant yesterday titled, “Chip Technology and Credit Cards.” This piece explores the technology a little further.
We’re seeing the term “RFID” popping up more often in the news lately. It’s an acronym for “Radio Frequency IDentification” and has been used in various forms for a number of years.
RFID is a generic term for technologies that use radio waves to automatically identify people or objects. There are several methods of identification, but the most common is to store a serial number that identifies a person or object, and perhaps other information, on a microchip that is attached to an antenna (the chip and the antenna together are called an RFID tag).
An RFID system consists of a RFID tag and a reader.
The reader sends out electromagnetic waves. The tag’s antenna is tuned to receive these waves. The reader converts the radio waves reflected back from the RFID tag into digital information that can then be passed on to computers that can make use of it.
A passive RFID tag draws power from the electromagnetic field created by the reader and uses it to power the microchip’s circuits. The chip then modulates the waves that the tag sends back to the reader and the reader converts the new waves into digital data.
The ancestor of the modern RFID was patented in 1973, but the first patent associated with the abbreviation “RFID” was granted in 1983. So, the general technology has been around for a while. But the key to widespread use has been the miniaturization of the tag and (to a lesser degree), the reader.
Some of the original uses for RFID were expected to be in the fields of transportation, banking, security, and medical history. In those days, no one had yet anticipated the possibilities available in retail commerce.
RFID tags can be passive or active. An active tag has an on-board battery and automatically transmits its ID signal. A passive tag is cheaper and smaller since it carries no battery – it depends on the radio energy transmitted by the reader for power. Tags for different purposes also operate on different frequencies and have different costs, transfer rates, directionality, and susceptibility to interference.
As noted before, the miniaturization of the RFID chips is what has expanded the horizon for the technology, but while the chips themselves have been reduced in size, the antennas are beginning to be a limiting factor.
Hitachi is the current record holder for the smallest chip, at .05mm x .05mm. The dust-sized chips can store 38-digit numbers. A major challenge is the attachment of antennas, thus limiting read range to only millimeters for that tiny chip.
Speaking of range, the question naturally follows: what is the range at which a chip can be read by a reader? The answer is that it depends on several factors, not the least of which is the frequency at which the system operates. The read range of passive tags (tags without batteries) in general will be a foot or less. High frequency tags are read from about three feet and UHF tags are read from 10 to 20 feet.
An application such as tracking railway cars requires reading at greater distances and uses batteries to boost read ranges to 300 feet or more.
And finally, here is one of the FAQs on the RFID site that I found interesting: “Will governments be able to use RFID to spy on people?”
And their answer was: “If companies choose to put RFID tags in clothes and items consumers carry around, such as wallets, and consumers choose not to kill the tags in these items, it might be possible for governments to use RFID tags for surveillance.
But they would have to have access to the database of information related to the tags’ EPCs, and it would be easy for individuals to avoid being tracked. RFID readers must emit radio waves to read tags. The signals from a reader can easily be detected and blocked.”
OK, got that? Applying the technology available today, it’s not really feasible; it’s possible, but not feasible. But (and that’s a big BUT), how about 20-30 years from now, when battery and chip technology and miniaturization has evolved? And access to a database of information? Ever hear of the NSA?
So I’m just a little bit paranoid; I guess I can remove my tinfoil hat now (and slip into my tinfoil coveralls) because I just KNOW that they’re after me.
If you’re interested in reading more about RFID, check out the FAQ section of the RFID Journal site HERE.