Introduction to Radio Frequency Identification (RFID)

In past few recent years, the automatic identification techniques have become quite more than popular and they have also find their places into the core of service industries, manufacturing companies, aviation, clothing, transport systems and much more. And, it’s pretty clear by this point of time that the automated identification technology especially RFID, is highly helpful in providing information regarding the timings, location and even more intense information about people, animals, goods etc. in transit. RFID is responsible for storage of large amount of data and is reprogrammable also as in contrast with its counterpart barcodes automatic identification technology.

In everyday life, the most common form of an electronic data-carrying device if often a smartcard which is probably based upon the contact field. But, this kind of a contact oriented card is normally impractical and less flexible to use. On the contrary, if we think of a contactless card with contactless data transferring capabilities, it would be far more flexible. This communication happens between the data carrying device and its reader. Now, this situation may further appear as ideal if it so happens that the power for the data carrying device comes from the reader by making use of the contactless technology. Because of this specific kind of power transferring and data carrying procedures, the contactless automatic identification systems are termed as Radio frequency Identification Systems.

What is RFID?

The term RFID stands for Radio Frequency Identification. Radio stands for invocation of the wireless transmission and propagation of information or data. For operating RFID devices, Frequency defines spectrum, may it be low, high, ultra high and microwave, each with distinguishing characteristics. Identification relates to identify the items with the help of various codes present in a data carrier (memory-based) and available via radio frequency reading. The RFID is a term which is used for any device that can be sensed or detected from a distance with few problems of obstruction. The invention of RFID term lies in the origin of tags that reflect or retransmit a radio-frequency signal. RFID makes use of radio frequencies to communicate between two of its components namely RFID tag and the RFID reader. The RFID system can be broadly categorized according to the physical components of frequency and data.

Radio Frequency Identification (RFID)

Physical components of the RFID system include, but are not limited to, the following: numerous RFID tags and RFID readers and Computers. The factors associated with the RFID tags are the kind of power source its has, the environment in which it operates, the antenna on the tag for communication with the reader, its corresponding standard, memory, logic applied on the chip and application methods on the tag. The RFID tag refers to a tiny radio device also known as radio barcode, transponder or smart label. This tag is comprised of a simple silicon microchip which is attached to a small flat antenna and mounted on a substrate. The entire device can then be encapsulated in various materials dependent upon its intended usage. The finished RFID tag can then be attached to an object, typically an item, box or pallet. This tag can then be read remotely to ascertain position, identity or state of an item. The application methods of an RFID tag may take the forms attached, removable, embedded or conveyed. Further, the RFID tags depend upon the power source which may be a battery in case of active-tags and an RFID reader in case of passive tags.  In context of the environment in which the tag operates, the role of temperature range and the humidity range comes into picture.

The RFID reader is also referred as interrogator or scanner. Its purpose is to send and receive RF data from tags. The RFID reader factors include its antenna, polarization, protocol, interface and portability. The antenna for communication in case of the RFID reader may be internal or external and its ports may assume the values single or multiple. The polarization in case of an RFID reader may be linear or circular and single or multiple protocols may be used. In an RFID reader, Ethernet, serial, Wi-Fi, USB or other interfaces may be used. Regarding portability associated with the reader, it may be fixed or handheld.

Apart from the RFID tags and readers, host computers are also amongst the part of the physical components of an RFID system. The data acquired by the RFID readers is passed to the host computer which may further run a specialist RFID software, or middleware to filter the data and route it to the correct application to be processed into useful information.

Apart from the physical components of an RFID system, the RFID system may be perceived from the frequency perspective. In RFID systems, the frequency may further be classified according to the signal distance, signal range, reader to tag, tag to reader and coupling. The signal distance includes the read range and the write range. The signal range here in case of RFID systems reflects the various frequency bands i.e. LF, HF, UHF and Microwave. Further, the reader to tag frequency may assume single frequency or multiple frequencies. In case of tag to reader frequency, it may be subharmonic, harmonic or an harmonic. The data sub classification in RFID systems includes, the security associated with the RFID systems, multi-tag read co-ordination and processing. In the similar context, public algorithm, proprietary algorithm or none are applied for the security associated with the RFID systems. The multi-tag read co-ordination techniques used in the latest RFID systems include SDMA, TDMA, FDMA and CDMA. The processing part is composed of the middleware which further has its own architecture which may assume a single or multi-tier shape and its associated location may be reader or the server.


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