RFID or Radio Frequency Identification is the name for a set of techniques used for the identification and tracking of various items.
In the mid 1980’s the cost and size of electronic circuitry reduced dramatically. At the same time power consumption of microcircuits fell even more markedly. These advances made it possible for the production of low cost “tags” that could economically be used once only in some cases. At the same time, these advances spawned the “SmartCard” which was typically a low cost credit card size and thickness memory card, which was cheap enough to be sold as a disposable phone card.
Various types of tags were developed with differing capabilities and limitations. One of the earliest of the low cost tags was the “Button”. This was an electronic memory with controlling circuitry, which was packaged in a fairly large “watch” battery case. Only one “Button” could be read at a time and it was necessary to hold the button against the reader contacts for a read to take place.
Subsequent tag developments led to contactless tags that operated in the low frequency range of approximately 128 kHz. These tags also had to be read one at a time and had a short read range. Many of these tag designs are still in production and are commonly used for gate opening etc. Although the tags are relatively expensive, the readers are cheap.
Tags that operated at 13.56 MHz were developed to offer improved range over the 128 kHz tags. They still, however, suffered from the problem that only one or a limited number of tags could be read at any one time. The read range of the 13.56 MHz tags, although better than that of the 128 kHz tags, was still severely limited with read ranges being typically under 1 meter.
The ability to produce efficient diodes that could be operated at frequencies approaching 1 GHz led to the development of UHF tags. These had the potential for large numbers of tags to be in the reader field simultaneously. This in turn caused a requirement for an effective anti-collision mechanism, which would allow multiple tags to be read in an orderly fashion. Currently produced tags and reader systems allow many tags (typically a few hundred) to be read simultaneously by a single reader. At the same time, ranges have steadily climbed and read ranges in excess of 5 meters can readily be achieved under allowed South African power levels.
Much of the aforementioned development took place in South Africa and much was pioneered by the CSIR. Currently many systems use technology that is licensed under CSIR patents. Of course, this is a big and expensive field and no single company or even country can go it alone. For this reason, international standards have emerged and users are likely to insist upon systems that comply with these standards.