Radio Frequency Identification (RFID)

By Jith Crs

The term Radio Frequency Identification is used for automatically identifies an object that transmits the identification (in the form of a unique serial number) of an object wirelessly, using radio waves.

Radio Frequency IDentification abbreviated, as RFID is a Dedicated Short Range Communication (DSRC) technology. It is very similar to Barcode identification systems but it got a major difference. RFID does not require line-of-sight access but bar code scanning it is must.

RFID technologies are grouped under the more generic Automatic Identification (Auto ID) technologies. The existing Identification systems are not sufficient for today use as their low storage capacity and the another fact that they cannot be reprogrammed.

A feasible solution is putting the data on silicon chips and contact less transfer of data between the data carrying device and its reader. The power required to operate the data-carrying device would also be transferred from the reader by contact less technology. These all lead to the development of RFID devices.

RFID TECHNOLOGY AND ARCHITECTURE: In an RFID system, the RFID tag, which contains the tagged data of the object, generates a signal containing the respective information, which is read by the RFID reader, which then may pass this information to a processor for processing the obtained information for that particular application.

With RFID, the electromagnetic or electrostatic coupling in the RF (radio frequency) portion of the electromagnetic spectrum is used to transmit signals. An RFID system consists of an antenna and a transceiver, which read the radio frequency and transfer the information to a processing device (reader) and a transponder, or RF tag, which contains the RF circuitry and information to be transmitted. The antenna provides the means for the integrated circuit to transmit its information to the reader that converts the radio waves reflected back from the RFID tag into digital information that can then be passed on to receivers in which it can analyze the data.

Thus, an RFID System would following three components:

RFID tag or transponder

RFID reader or transceiver

Data processing subsystem

The transponder, or RF tag tags can be either active or passive. While the active tags have on-chip power, passive tags use the power induced by the magnetic field of the RFID reader. Thus passive tags are cheaper but it got a limitation that, it work in a limited range (RFID Frequencies: RFID systems are differentiated based on the frequency range it works. The different ranges are Low-Frequency (LF: 125 - 134.2 kHz and 140 - 148.5 kHz), High-Frequency (HF: 13.56 MHz) and Ultra-High-Frequency (UHF: 850 MHz - 950 MHz and 2.4 GHz - 2.5 GH).

RFID, Tag, transponder, Radio, Frequency, Identification

Ultra-High-Frequency RFID systems offer transmission ranges of more than 90 feet. But wavelengths in the 2.4 GHz range are absorbed by water, which includes the human body, which gives some limitations of its use.

The standards used in RFID: RFID standards mainly stressed in the following areas

Air Interface Protocol - which deals with the way in which tags and readers communicate

Data Content - Organizing of data in the Tags

Conformance - Tests that required for the products to check that, it meet the standards

EPC standards for Tags:

Class 1: a simple, passive, read-only backscatter tag with one-time, field-programmable non-volatile memory.

Class 0: read-only tag that was programmed at the time the microchip was made

Different applications of RFID: Some other areas where passive RFID has been applied in recent past are:-Person Identification, Identification of location of a person, Animal/Pet Identification, Food Production Control, Vehicle Parking Control/Monitoring, Toxic Waste Monitoring, Valuable Objects Insurance Identification, Asset Management, Inventory tracking, Access Control etc

RFID Security:The basic privacy concerns associated with an RFID system is the ability of unauthorized tracking of anybody without consent. These are the ways in which RFIDs can be used to bypass personal privacy. By placing RFID tags hidden from eyes, and using it for stealth tracking or using the unique identifiers provided by RFID for profiling and identifying consumer pattern and behavior or using hidden readers for stealth tracking and getting personal information.

Because of these reasons some attempts are made to maintain privacy and reduces the above disadvantages.

RSA Blocker Tags: Any reader that attempts to scan tags without the right authorization, thus confusing the reader to believe that there are many tags in its proximity.

Kill Switches: The consumer will be given an option of disabling the RFID tag, hence avoiding the possibility of stealth tracking and profiling.

Jith is an Electrical and Electronic Engineer by profession from Southern india. he has good experience in sensors, Data acquisition systems, communication protocols etc.

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