Passive tags have no power. The signal comes from readers induces a small electric current sufficient to operate the CMOS integrated circuit of the tag, so you can generate and transmit a response. Most passive tags used Backscatter received on the carrier, ie, the antenna must be designed to obtain the energy necessary to operate at the same time to transmit the response Backscatter. This response can be any type of information, not just a code identifier. A tag may include nonvolatile memory, write (eg EEPROM).
Passive tags typically have distances of practical use between 10 cm (ISO 14443) and reaching a few meters (EPC and ISO 18000-6), depending on the frequency of operation and the design and size of the antenna. For its conceptual simplicity, are obtainable through a process of printing the antennas. Since not require a power failure, the device can be very small, can be included on a sticker or inserted under the skin (low-frequency tags).
In 2006, Hitachi developed a passive device called -Chip with a size of 0.15 to-0, 15 mm without antenna, thinner than a sheet of paper (7.5 m). is used SOI (Silicon-on-Insulator) to achieve this integration. This chip can transmit a unique identifier attached to the 128 bits in their manufacture, which can not be modified and gives authenticity to it. Has a maximum read range of 30 cm. Hitachi in February 2007 presented an even lower 0.05 to-0, 05 mm and thin enough to be able to be integrated into a sheet of paper. These chips have the storage capacity and can operate at distances up to a few hundred meters. Its main drawback is that the antenna must be at least 80 times larger than the chip.
Alien Technology (fluidic Self Assembly), SmartCode (Flexible Area Synchronized Transfer) and Symbol Technologies (PICA) state has processes in various stages of development that can further reduce costs through manufacturing processes in parallel. Businessman Citation needed These means of production could lower costs and more direct models of economies of scale of a major sector of the manufacturingof silicon. This could lead to a greater expansion of the technology of passive tags.
There are tags made of semiconductor-based polymers developed by companies around the world. In 2005 Philips introduced PolyIC and simple tags in the range of 13.56 MHz using this technology. If you enter the market successfully, these tags would be produced in a print magazine, with production costs much lower than silicon tags, serving as an alternative fully printed, as the existing barcodes. However, it is necessary to overcome technical and economic aspects, taking into account that silicon is a technology that takes decades to enjoy multi-million dollar development investments that have resulted in a lower cost than the conventional printing.
Due to concerns over energy costs and the response of a passive RFID tag is necessarily brief, typically just an ID number (GUID). The lack of a power supply makes the device itself can be quite small: there are products available commercially that can be inserted under the skin. In practice, the passive tags have read distances ranging from about 10 millimeters to about 6 meters, depending on the size of the tag antenna and the power and frequency at which the reader operates. In 2007, the shortest commercially available device such half-0.05 mm to 0.05 mm, and thinner than a sheet of paper, these devices are practically invisible. Citation needed
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| Design and Optimization of Passive UHF RFID Systems by Jari-Pascal Curty, Michel Declercq, Catherine Dehollain, and Norbert Joehl (Kindle Edition - Oct 25, 2006) - Kindle Book | Global RFID: The Value of the EPCglobal Network for Supply Chain Management by Edmund W. Schuster, Stuart J. Allen, and David L. Brock (Hardcover - Feb 1, 2007) | Passive RFID tested in the supply chain.: An article from: Navy Supply Corps Newsletter by Jerry Zamer (Digital - Nov 29, 2005) - HTML | |||
