Radio frequency identification (RFID)

Radio frequency identification (RFID) is an advanced automatic identification technology. It is used to identify, track, sort and detect an infinite variety of objects, including people, vehicles, garments, containers, totes and pallets.

It can be used in applications such as proximity access control, time-and-attendance management, vehicle identification, laundry/textile identification, asset tracking, inventory control and factory automation.

RFID relies on radio frequency or "waves" between a card or tag and a reader in order to make an identification. Because RFID is a "contactless" technology, it requires neither contact with a reader or a direct line of sight to a reader (as does bar code technology).

An RFID tag is based on a chip or integrated circuit (IC). A tag insert or inlay is the IC attached to an antenna, which is usually printed or etched on a substrate material. The tag itself is the inlay plus its encapsulated protective packaging. The packaging can be flexible or stiff, as the application warrants.

An RFID system typically consists of a radio-enabled device that communicates with or "interrogates" a tag or label, which is embedded with a single chip processor and an antenna.

The "interrogator" or RFID reader may be a fixed antenna or it may be portable, like a bar code scanner. The tag itself is an extension of the bar code labels you see everywhere today, but with more intelligence.

The advantage of these more intelligent systems is that, unlike barcode tracking systems, an RFID system can read the information on a tag without requiring line of sight or a particular orientation. This means that RFID systems can be largely automated, reducing the need for manual scanning.

In the back end of the system, a host computer stores all collected data within a database. Since RFID tags can also carry data, tags can serve as data transfer agents, synchronizing disparate information systems. Tags may carry a product's history or genealogy, and may interact and communicate with manufacturing production systems for increased automation and process error proofing.

An RFID system typically includes the following components:

A tag or label that is embedded with a single chip processor and an antenna. The tag is an extension of the bar code labels you see in stores today, but with more intelligence.

Tags may be read-only or read/write. Read-only tags are most like bar codes because the encoded data cannot be changed and is often only a serial number that is used to retrieve additional descriptive data (such as item type, date of manufacture, etc.) from a database. Read/write tags function like computer disks because they can be rewritten and updated an unlimited number of times, and may offer "locked" sections that cannot be altered.

A radio enabled device that communicates with or interrogates the tag for reading and writing.



Tag types and tag selection

When selecting a tag or insert, you must first consider the general performance characteristics and the regulatory requirements associated with the permitted frequencies for your country of operation.

There are two types of RFID tag: active and passive.

RFID Tag Technologies
Active	Passive
Battery powered	Powered by reader
Read-write and read only versions available	Read-write and read only versions available
Longer read ranges25 to 100 feet	Shorter read rangesInches to 20 feet
Higher tag costs ($20 to $70 per tag)	Lower tag costs (at least $1 per tag)
2D location systems possible	Item ID
Example: toll booths	Example: item management

RFID deployments tend to use unlicensed frequencies for their obvious cost benefits. There are four commonly used frequencies: low frequency (LF) 125/134.2 KHz, high frequency (HF) 13.56 MHz, ultra high frequency (UHF) (including 869 and 915 MHz) and microwave (at 2450 MHz, a band familiar to ISPs).

A tag's read range performance is usually considered the primary gauge of its suitability for a particular application. It is important to remember that not all applications require maximum range.

Tags in the LF-HF band have a range of 1 to 18 inches, while passive UHF tags can reach up to 20 feet, and microwave tags can reach 1 to 6 feet. The ranges greatly depend upon the surface on which the tag is mounted.

Each tag can be "tuned" to work with the material it is mounted on, whether metal, glass, plastic, wood, or air. If you take a tag designed for a glass windshield at 915 MHz, and attach it to a wooden pallet, you may not be able to read it. Any experienced RF user will know that each frequency requires a slightly different antenna shape.

Benefits of RFID

RFID benefits the user similarly to other automatic identification technologies in that it reduces the need to collect data by cumbersome means like paper and pencil. Often the amount of data to be collected is so overwhelming and the time needed to process the information is so long that the only practical method of collecting the data is automatically with computer technology. Automatic data acquisition improves the value of the information in a system by making the information available sooner. In a manufacturing facility the value of finding out that work in process has been misrouted is valuable if discovered quickly.

RFID is ideal for dirty, oily, wet or harsh environments.

RFID tags and readers have no moving parts so the system rarely needs maintenance and can operate for extended periods of time.

RFID is an inexpensive form of automatic identification when measured over time.

Unlike bar codes, RFID is very difficult to copy and is ideal for confidential identification of people or assets.

RFID is fast: The tag and reader communicate in virtually milliseconds. Actual throughput depends on communication with the host computer, but the total speed of a good read is 30 to 100 milliseconds on a typical read-only tag.

Typical RFID tags will survive at minus 40 degrees centigrade to 200 degrees centigrade

Much hyped, RFID is the subject of several myths.

Myth 1: RFID will replace bar code

In reality, these are two complementary technologies. While RFID can store more data than bar code, bar code is much cheaper. Most consumers are familiar with linear (one dimensional) bar codes. Many industrial applications employ a denser rectangular (two dimensional) bar code which can contain a significant amount of data.

Bar code is so reliable and cost effective that it will continue to provide a better ROI than RFID in many new deployments. Bar code is synergistic with RFID, and serves as a useful backup to RFID. In fact, all Tech Center RFID implementations to date also employ bar code technology.

RFID tag inlays may be affixed directly behind bar code labels, and programmed by new Intermec and Zebra Bar code label printers equipped with the RFID tag write ability.

Bar Code vs. RFID
Bar Code	RFID
Optical technology	RF technology
line of sight only	non line of sight
read only	read only or read/write capable
Can carry data (2D only)	Can carry data (depending on tag vendor)

The real savings from RFID comes not from simply deploying the technology, but from improving the entire business process. It's therefore no accident that many early implementers of RFID, like Tech Center, have experience implementing CRM and ERP, which are other technologies whose true value can only be realized after significant changes in business processes.

Compared to bar code, RFID enables greater automation of the data collection process. With RFID, non line of sight (NLOS) interrogation is possible. With circular polarized antennas, the beam does not need to be oriented manually, as it may have to be with a linear bar code. It enables the reading of multiple tags at the same time and even allows the reading of selective tags, as determined by identification data residing on the tag.

RFID (and bar codes) allow data to be securely transmitted from one company to another. Many companies use independent suppliers. Data from those suppliers can be carried on tags and uploaded automatically to the receiving company's ERP system the moment a component is delivered.

Most companies are accustomed to knowing what's in their warehouse, but RFID promises to enable them to drill deeper, tracking each pallet, lot, or even each unit.

In turn, an RFID tag will allow companies to track each pallet, lot, and unit long after it has left the factory or warehouse. Manufacturers will be able to track product genealogy, understanding better the creation of successes and defects. Product recalls could be far more focused, saving massive amounts of money, especially in the health care and automotive industries.

Companies will therefore have better data about post-production product performance. Taking the automotive industry as an example, a car would consist of individually tagged components. The car body, engine, each tire, and each air bag would have a separate tag. Data could be collected at repair shops or accident sites.

Even within the factory, tags could enable foolproof manufacturing. An auto body tag could tell a factory person or robot, "please install a red steering wheel on me." If a mistake is made, the unit can be tracked and fixed later without stopping the assembly line, or it can be fixed immediately.

The RFID technology and its uses will continue to change, but we don't know exactly how. Read/write technology can meet sophisticated application needs today but also provides the flexibility to accommodate future changes. This flexibility enables users to fully leverage their RFID investment by adapting the technology to meet future needs and extend the life cycle of the system.

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