Passive RFID Tag

RFID, which stands for Radio Frequency identification, is a very promising technology in terms of saving of time & providing enhanced security. The RFID tags being used in NIT Rourkela for Management of Library books. The system has a very wide application then the stated afore. These tags can be used in grocery stores to address to the problem of Long checkout lines, which is one of the biggest complaints about the shopping experience. Soon, these lines could disappear when the ubiquitous Universal Product Code (UPC) bar code is replaced by smart label­s, also called RFID tags. RFID tags here work as intelligent bar codes that can talk to a networked system to track every product that you put in your shopping cart. With the application of RFID tags in the grocery stores, you will no longer have to wait as someone rings up each item in your cart one at a time. Instead, these RFID tags will communicate with an electronic reader that will detect every item in the cart and ring each up almost instantly. The reader will be connected to a large network that will send information on your products to the retailer and product manufacturers. Your bank will then be notified and the amount of the bill will be deducted from your account. So No lines, no waiting. J

Outside the realm of retail merchandise, RFID tags are tracking vehicles, airline passengers, Alzheimer’s patients and pets. Soon, they may even track your preference for chunky or creamy peanut butter. Some critics say RFID technology is becoming too much a part of our lives — that is, if we’re even aware of all the parts of our lives that it affects. RFID tags hold a potential future to be implanted in humans so as to track his movements & make himself the password for all activities. For example, You won’t need to carry any credit card/cash to shop you yourself are the key to your bank account. Hence RFID makes the human, the key holder of his/her own life. The criminals can be easily tracked down on their movements.

History of RFID

The history of RFID can be directly related to a similar technology employed by the Allies in World War 2 called IFF (Identification Friend or Foe). The function of this technology was to identify whether an incoming plane was a friend or foe by using coded radar signals. These signals would trigger the aircrafts transponder, and a correct reply indicated a friendly military or civilian aircraft. After the war, scientists and researchers began to explore the use of RFID to store and relay information.

Radio Frequency Identification presented one major obstacle before it could become a feasible technology; finding a suitable power source. It took roughly thirty years for technology and research to produce internal power sources for RFID tags and chips.

Types Of RFID Tags

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

Passive RFID tags

Passive RFID TagPassive RFID Tag

They have no internal power supply. Instead, a small electric current is created in the antenna when an incoming signal reaches it. This current provides enough power to briefly activate the tag, usually just long enough to relay simple information, such as an ID number or product name. Because passive RFID tags do not contain a power supply, they can be very small in size, sometimes thinner than a piece of paper. These tags can be activated from a distance of ten millimeters to over 6 meters away.

Active RFID tags

Active RFID TagActive RFID Tag

These do contain an internal power source, which allows for a longer read-range and for a bigger memory on the tag itself. The power source also makes it possible to store information sent by the transceiver. Active RFID tags are larger than passive tags, usually slightly bigger than a coin. Their battery can last up to seven years. They can be read from many meters away, and generally have a battery life of about ten years. Advantages of active tags include accuracy, reliability, and superior performance in adverse environments, such as damp or metallic.

Being cheaper to manufacture, most RFID tags are of the passive variety. Analysts predict that ever-lowering costs and growing demand will eventually lead to the widespread usage of RFID technology on a global scale.

The four most common tags in use are categorized by radio frequency: low frequency tags (125 or 134.2 kHz), high frequency tags (13.56 MHz), UHF tags (868 to 956 MHz), and microwave tags (2.45 GHz).

Current RFID Applications

Current RFID use has spread to many, many varied fields:

  • Medical: tags are placed on prescription pill bottles for the visually impaired. A special reader provides audible information on the name, instructions and warnings of the prescription.
  • Animal Identification: low frequency tags are implanted in animals, wild or domestic, which can be read to provide information such as gender, name, diseases etc. As well, these tags allow lost pets to be returned to their owners.
  • Tracking: High frequency RFID tags are used to track library books, baggage, ID tags, warehouse inventory and even credit cards. American Express has a new service called Express Pay, featured on the American Express Blue credit card, which utilizes RFID technology.
  • Geology/Vulcanology – RFID transceivers relay seismic information to specialized readers, greatly simplifying the collection of data.
  • Automotive: Michelin has spearheaded a program to embed RFID tags in their tires. This will help track down problems should a recall have to be utilized. As well, some Toyota and Lexus models feature a Smart Key option, which uses an active RFID tag to allow the driver to unlock doors and roll down windows without having to take the key out of their pocket.
  • Human: As frightening as it may seem, RFID technology is already tracking human beings. Inmates at select prisons around the United States are issued special wristbands with RFID tags embedded within. These tags constantly relay the location of the prisoner to a computer, as well as raise an alarm should the band be tampered with. In more extreme cases, RFID chips have been implanted into arms, legs etc. of various individuals. For example, the Mexico police department has had over 170 members of its force implanted with the Verichip. This allows them to access databases and, in rare instances, track an officer in case of a kidnapping.
  • Border Security – RFID Chips implemented for the USA Canada Nexus program

Research and technological advances will lead to prolific achievements in RFID devices. The ultimate goal is to eventually replace all UPC and barcodes with RFID tags, but that is highly unlikely in the near future due to expenditure needed. Another goal is to utilize the uniqueness of each individual RFID code for combating theft of merchandise by tracking it as it moves form location to location. Research is also being undertaken to create an ink with RFID properties.

Representatives from EPCGlobal, which includes major companies around the world such as Wal Mart and The Gillette Company, are working on an international standard of use for RFID. The objective is to eventually use the EPC (Electronic Product Code) and RFID to identify any item, in any industry, anywhere in the world.

Experts in the medical community have suggested numerous potential uses for RFID tags. Special tags could keep track of patient records and allow relevant medical staff to access them with the wave of a reader. Chips could even be embedded into patients containing medical information, greatly easing the strain of home care workers and potentially saving lives.

There are plenty of home uses as well. “Talking” fridges may one day inform the owner of expiry dates, and implanted RFID tags will allow a house to recognize which individual is in which room, thereby adjusting the lighting and heat of that room to the individual’s preferences.

Components of an RFID System

A comprehensive RFID system has three components: (1) RFID tags that are electronically programmed with unique information; (2) readers or sensors to interrogate the tags; and (3) a server or docking station on which the software that interfaces with the automated system is loaded. It is also possible to distribute the software among the readers and sensors.


Each paper-thin tag contains an etched antenna and a microchip with a capacity of at least 64 bits. There are three types: “read only”, “WORM,” and “read/write.” Tags are “read only” if the identification is encoded at the time of manufacture and not rewritable. This type of tag contains nothing more than item identification. It can be used for items acquired after the initial implementation of RFID and by libraries that have collections without barcodes. Such tags need not contain any more than 96 bits.

“WORM” (Write-Once-Read-Many)” tags are programmed by the using organization, but without the ability of rewriting them later. They can be used when a retrospective conversion of a collection that is already barcoded is undertaken. The main advantage over read only tags is that information in addition to the identification number can be added. However, it must be information that won’t need to be changed. That could be an author and/or truncated title if the tag has enough capacity, but not library location, circulation status, monetary transactions & daily records.

“Read/write tags,” which are chosen by most libraries, can have information changed or added. For example, an organisation might add an identification code for each branch. That information could be changed were the holding location subsequently changed. When a vendor includes a “theft” bit that can be turned on and off, the RFID tag can function much like an EM or RF tag. In library RFID, it is common to have part of the read/write tag secured against rewriting, e.g.,. the identification number of the item. All of the tags used in RFID technology for libraries & inventories are “passive”.

The tags used by RFID vendors are not compatible even when they conform to the same standards because the current standards only seek electronic compatibility between tags and readers. The pattern of encoding information and the software that processes the information differs from vendor to vendor, therefore, a change from one vendor’s system to the other would require retagging all items or modifying the software.

A few Organizations have placed RFID tags on staff and patron identification cards. Not only does that identify patrons for charging and discharging of materials, but also for access to restricted areas, services and even tracking their movements.

A “smart” card, which is an RFID card with additional encryption, is an alternative to merely adding an RFID tag to a patron card. That would make it possible to make it into a “debit” card, with value added upon pre-payment and the value subtracted on usage of different services like Library Dues, Restaurant Bills , Academic Dues etc.


A typical system includes several different kinds of readers, also known as sensors. They can be installed at exits. These are radio frequency devices designed to detect and read tags to obtain the information stored thereon. The reader powers an antenna to generate an RF field. When a tag passes through the field, the information stored on the chip in the tag is decoded by the reader and sent to the server which, in turn, communicates with the automated library system when the RFID system is interfaced with it. While there is software in each reader to facilitate communication with the server and/or with staff, most of the software supplied by the RFID system vendor is on the server when one is included in the system. When there is no server, most of the software is on the readers, although some may be on a docking station.

For Libraries & Stores, the types of readers include staff workstations for circulation desk charging and discharging, patron self-charging stations, and longer-range walk-through exit sensors to detect and read an RFID tag passage for purposes of determining whether it is a charged (authorized/no alarm) or discharged (non-authorized/alarm) event. The exit sensors are sometimes called “antennae,” but that is not correct because an antenna is only one component of an exit sensor. It is also possible to install a reader in a book drop to discharge materials as they pass the reader. Finally, there is a portable device that consists of a scanning gun attachment to read a group of items on the shelves for purposes of locating missing and misplaced items.

Programmers or conversion stations range in price from as little as $2,500 to as much as $5,000. Readers for use at the circulation desk typically cost $2,500 or more each. They can be placed on the circulation counter or built-in. Discharging can be done on the same units, or on one or more dedicated units away from the service counter. Check-in is particularly rapid because the materials can be moved over the unit without regard to the orientation of the material and no conversation with patrons is involved.

Patron self-charging stations are similar to those which have been available for years and are similar in cost, approximately $18,000-22,000. A number of models can support not only conventional barcoded library cards, but also magnetic strip cards and smart cards. Some models can also be used for patron self-discharging. That increases the cost of the unit by at least $2,500.

A patron self-charging station can handle up to 20,000 transactions per month.

RFID exit sensors at exits look much like those installed in libraries for the last several decades, however, the insides are very different. One type reads the information on the tag(s) going by and communicates that information to a server. The server, after checking against the circulation database, activates an alarm if the material is not properly checked-out. The units cost $3,500-6,000 each. Another type relies on a “theft” byte in the tag that is turned on or off to show that the item has been charged or not. It is then not necessary to communicate with the circulation database.

A bookdrop reader can automatically discharge library materials and reactivate security. Since they have already been checked-in, they can go directly back onto the shelves. These units can also be used with sorter and conveyor systems. Bookdrop readers usually are the same as circulation desk readers and cost no more than $2,500 plus the cost of installation into a desk or wall. ATM-type units cost at least $25,000, and an ATM-type unit with a sorter and five or more bins costs from $45,000 to $200,000 or more.

The portable scanner or inventory wand, which is priced at $2,500 or more, can be moved along the items on the shelves without touching them. The data goes to a storage unit ($2,000 or more) which can be downloaded at a docking station or a server later on, or it can go to a unit which will transmit it to the server using wireless technology ($3,000 or more).

Server/Docking Station

The server is the heart of some comprehensive RFID systems. It is the communications gateway among the various components. It receives the information from one or more of the readers and exchanges information with the circulation database. Its software includes the APIs (Applications Programming Interface) necessary to interface it with the automated library system. The server typically includes a transaction database so that reports can be produced. A server costs as much as $15,000, more than two-thirds of which is the software. A vendor may choose not to use a server by substituting a less expensive docking station and increasing the amount of software in the readers.

How RFID Works

In Resource Tracking System, the readers connect to an Ethernet network using twisted-pair, fiber optics or Varis’ Smart Com Leaky Feeder, The Smart Tag’s web based software distribution enables multiple user access and provides a real-time view of resource location network wide.

Resource Tracking

RTLS (Real Time Location Systems) can locate objects using RFID tags. Essentially, this means that it can provide you with a substantially more specific location for an asset (a car) by using the same network you use today to access the Internet. RTLS uses tags that are WiFi and does not require proprietary RFID readers.


The tags used to track assets are non-contact and non-line-of-sight. This means that you don’t have to “swipe” your card for an RFID / RTLS system to identify you. You also don’t have to walk up to the object and “read” a bar code with a traditional scanner.

Quite simply, RFID / RTLS is a revolution in how inventory will be tracked and managed in years to come. Wal*Mart and Target are implementing RFID in a huge way with the majority of it suppliers.

In order to utilize RFID you need two things: an RFID capable reader and an RFID tag. Readers can generally be either portable or fixed (i.e. immobile). In general, tags can be either “passive” or “active”. For RTLS, the Wireless Access Point (WAP) takes the place of the RFID reader and the tags are “WiFi” active tags.


Here’s how the InClass system for Student Attendance & Tracking works: A unique 15-digit ID number is written to each tag and associated with the name of the student to whom it is issued. As the students pass through the reader-generated interrogation field under a doorway, the reader sends the tags’ unique ID numbers to a central server. InCom has developed a software program, installed on the server, that collects the tag data and uploads a list of present, absent and tardy (based on when they enter the classroom) students to a PDA that is issued to the teacher. The upload is done wirelessly over an 802.11b Wi-Fi protocol. The teacher can then perform a visual check on the InClass-generated attendance list by scanning the room to reconcile what the list says with what she sees in the classroom. Once confirmed, the list is submitted wirelessly via the same PDA to school administrators, who are required to file attendance records to a state board of education.

For Library Theft Detection

The information contained on microchips in the tags affixed to library materials is read using radio frequency technology regardless of item orientation or alignment (i.e., the technology does not require line-of-sight or a fixed plane to read tags as do traditional theft detection systems) and distance from the item is not a critical factor except in the case of extra-wide exit gates. The corridors at the building exit(s) can be as wide as four feet because the tags can be read at a distance of up to two feet by each of two parallel exit sensors. [The devices used for circulation and inventorying are usually called “readers” while the ones used at building exits are usually called “sensors.”]

Download the Fully Explained RFID Antenna Design

Advantages of RFID systems

Rapid charging/discharging

The use of RFID reduces the amount of time required to perform circulation operations. The most significant time savings are attributable to the facts that information can be read from RFID tags much faster than from barcodes and that several items in a stack can be read at the same time. While initially unreliable, the anti-collision algorithm that allows an entire stack to be charged or discharged now appears to be working well.

The other time savings realized by circulation staff are modest unless the RFID tags replace both the EM security strips or RF tags of older theft detection systems and the barcodes of the automated library system—i.e., the system is a comprehensive RFID system that combines RFID security and the tracking of materials throughout the library; or it is a hybrid system that uses EM for security and RFID for tracking, but handles both simultaneously with a single piece of equipment. [3M has developed readers that can do both concurrently except for videotapes and audiotapes. These have to be desensitized and sensitized in a separate operation]. In either case, there can be as much as a 50 percent increase in throughput. The time savings are less for charging than for discharging because the time required for charging usually is extended by social interaction with patrons.

RFID security and the tracking of personnel/material throughout the organization; or it is a hybrid system that uses EM for security and RFID for tracking, but handles both simultaneously with a single piece of equipment. [3M has developed readers that can do both concurrently except for videotapes and audiotapes. These have to be desensitized and sensitized in a separate operation]. In either case, there can be as much as a 50 percent increase in throughput. The time savings are less for charging than for discharging because the time required for charging usually is extended by social interaction with patrons.

Simplified patron self-charging/discharging

For patrons using self-charging, there is a marked improvement because they do not have to carefully place materials within a designated template and they can charge several items at the same time.

Patron self-discharging shifts that work from staff to patrons. Staff is relieved further when readers are installed in bookdrops.

In attendance & traking system there is no need for a person to be appointed for this task the system can effectively track all the personnel of an organization, thus increasing efficiency as each employee knows they are being tracked.

High reliability

The readers are highly reliable. Several vendors of RFID systems claim an almost 100 percent detection rate using RFID tags. Anecdotal evidence suggests that is the case whenever a reader is within 12 to 14 inches of the tags, but there appears to be no statistical data to support the claims.

There are fewer false alarms than with older technologies once an RFID system is properly tuned. The libraries contacted that have experience with both EM and RFID security systems, report a 50 to 75 percent reduction.

Some RFID systems have an interface between the exit sensors and the circulation system to identify the items moving out of the organization. Were a patron/employee to run out of the ware-house and not be intercepted, the management would at least know what had been stolen. If the patron/employee card also has an RFID tag, the management will also be able to determine who removed the items without properly charging them.

Other RFID systems encode the circulation status on the RFID tag. This is done by designating a bit as the “theft” bit and turning it off at time of charge and on at time of discharge. If the material that has not been properly charged is taken past the exit sensors, an immediate alarm is triggered. Another option is to use both the “theft” bit and the online interface to an automated system, the first to signal an immediate alarm and the second to identify what has been taken.

High-speed inventorying

A unique advantage of RFID systems is their ability to scan items on the ware-house without tipping them out or removing them. A hand-held inventory reader can be moved rapidly across a pile of items to read all of the unique identification information. Using wireless technology, it is possible not only to update the inventory, but also to identify items which are out of proper order.

Automated materials handling

Another application of RFID technology is automated materials handling. This includes conveyor and sorting systems that can move materials and sort them by category into separate bins or onto separate carts. This significantly reduces the amount of staff time required to ready materials for classifiaction.

Long tag life

Finally, RFID tags last longer than barcodes because nothing comes into contact with them. Most RFID vendors claim a minimum of 100,000 transactions before a tag may need to be replaced.

Disadvantages of RFID Systems

High cost

The major disadvantage of RFID technology is its cost. While the readers and sensors used to read the information are comparable in cost to the components of a typical EM or RF theft detection system, typically $2,500 to $3,500 or more each; a server costing as much as $15,000 may be required and the tags cost $.60 to $.85 each. It may be some time before the cost of tags comes down to $.50 or less.

Vulnerability to compromise

It is possible to compromise an RFID system by wrapping the protected material in two to three layers of ordinary household foil to block the radio signal. Clearly, bringing household foil into a library using RFID would represent premeditated theft, just as bringing a magnet into a library using EM technology would be.

It is also possible to compromise an RFID system by placing two items against one another so that one tag overlays another. That may cancel out the signals. This requires knowledge of the technology and careful alignment.

Exit sensor problems

While the short-range readers used for circulation charge and discharge and inventorying appear to read the tags 100 percent of the time, the performance of the exit sensors is more problematic. They must read tags at up to twice the distance of the other readers.

RFID Privacy and Controversies

Obviously, RFID privacy and the controversies surrounding the technology need to be resolved if RFID tags are ever going to be implemented on a global scale. The single greatest fear is one born of privacy invasion; the tags can be activated without the knowledge of the consumer. This would lead to targeted marketing and illicit tracking through tags the consumer may not even be aware of. In cases where RFID is used in credit or store cards, it could be possible to determine the identity of that particular consumer.

Another privacy controversy is that many RFID tags remain functional post-purchase, possibly allowing for surveillance and household inventories. As well, distance would not hinder the ability to read the tags; anyone with access to a high-gain antenna would be able to activate these RFID tags from a distance.

RFID technology may soon show up in passports and driver’s licenses, creating further controversies. Many countries want to utilize RFID to facilitate readability of passports and to expatiate customs procedures, which could lead to a compromise of an individual’s identity. The same technology has been proposed for use in driver’s licenses, with the purpose of hastening police checks, but would carry the same privacy issues as passport implantation.

RFID Security Concerns

One of the major RFID security concerns is the threat of illegal tracking. RFID tags could be read from a distance without the owner’s knowledge, leading to the disclosing of location or other sensitive information contained in the RFID tag’s memory. Another security concern is the cloning of RFID tags. This poses a problem for companies employing RFID technology for entry into their building, or for compromising payment methods, such as the Esso Speed pass.

Unfortunately, the technology does not currently exist to practically encrypt commercial RFID tags, though proposed low-encryption solutions include backward channeling and third-party agents. An industry standard label has also been suggested as a way to alleviate RFID security concerns.

RFID Today

The practical applications of RFID today are astounding. Any inventory could be instantly located in any warehouse, high risk security institutions are able to keep a constant eye on dangerous offenders, lost pets can be returned to their owners…the list goes on.

When a secure form of RFID is created for the consumer population and privacy issues are resolved, RFID tags will change the world. Organizations such as EPCGlobal are spearheading initiatives to standardize regulations and usage, and numerous reputable companies are spending billions of dollars and thousands of man-hours to perfect the technology.

RFID technology is continuously advancing, and the very near future will see science fiction become reality as Radio Frequency Identification makes its way into everyday functions.

Inplementation of RFIDs in Campus Management Systems

Download the PDF


RFID – A Case Study – SMJK Dindings, Lumut, Perak

RFID Technology for Libraries by Richard W. Boss

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