How Are RFID Tags Used and How Do They Work?

RFID Tags Technology: What Are RFID’s?

RFID stands for radio frequency identification. Radio frequency identification is a technology that uses devices called RFID transponders as an identification method. These transponders are used to store or send data that can be retrieved or sent by RFID tag or chip readers from a distance of a few feet to a few hundred feet. These RFID tags can be attached to or imbedded into a person, animal, product, and practically anything else, for the purpose of unique identification. The data that the RFID (Radio Freqency Identification Devices) tags reading device collects is sent to a database to be analyzed by people or software for various purposes.

Circuit Board Sends and Recieves Radio Wave Frequency Signals

Most RFID tags (Radio Freqency Identification Devices) have an integrated circuit board that stores and processes information, modulates and demodulates radio wave frequency signals, and completes other specific functions. The circuit board is attached to an antenna that transmits and receives radio wave frequency (RF) signals. There is also a developing technology that does not require the use of integrated circuit chips. This allows the tags to be printed directly onto items and reduces the cost of creating RFID tags (Radio Freqency Identification Devices).

History of RFIDs(Radio Frequency Identification Devices}

The first invention that was similar to a RFID tag or chip was invented in 1946 by Leon Theremin, which the Soviet Union used as an espionage tool. This device was more of a passive covert listening device, not a RFID tag or chip, but it is accredited to being the technology that was used to develop the current RFID tags or chips. In 1969 Mario Cardullo invented the first true ancestor of the current RFID tags or chips. This device was similar to modern passive RFID tags, as it had memory and a passive radio transponder. A few years later in 1973 the Los Alamos Scientific Laboratory created the technology for the first reflected power RFID tags (Radio Freqency Identification Devices).

Types of RFIDs Used on Products

There are three general types of RFID tags or chips: active RFID tags, passive RFID tags, and semi-passive RFID tags. Active RFID tags require a power source, such as a small lithium battery. Passive RFID tags do not have an internal power supply. Semi-passive RFID tags also have a battery, but the battery only gives enough power to run the microchip but not to broadcast the signal.

Active RFID Tags or chips

Active RFID tags tend to be more reliable then the other two types of RFID tags. Because active RFID tags have an “onboard” power source, they are able to transmit higher radio wave levels; this allows them to be read from greater distances and to be more effective in environments that are not favorable to RF signals. Such environments include, but are not limited to the following: water, humans, animals, metal containers and vehicles. Active RFID tags of a range of up to 1,500 feet and have a battery life of up to 10 years and have more memory capacity then passive RFID tags or semi-passive RFID tags. The two main drawbacks of this type of RFID tag or chip are that they are larger and cost substantially more to manufacture. An example of an organization that uses this type of RFID tag is the United States Department of Defense. The USDD has used this type of tag in supply chain management and cargo transportation for over 15 years.

Passive RFID Tags (Radio Freqency Identification Devices)

Passive RFID tags do not have an internal power supply; rather an electrical current is induced in the antenna by an incoming radio frequency. This provides enough power for the integrated circuit in the RFID to transmit a response. The antenna is designed to collect power from the incoming signal and to transmit what is known as a backscatter signal. Passive RFID tags have relatively short read distances compared to active RFID tags and semi-passive RFID tags. The normal distance is from about 4 inches to a few feet. The distance depends on the antenna size and the chosen radio frequency. Because there is no power supply a passive RFID can be quite small compared to the other types of tags. This type of tag is the most commonly used tag in logistics.

Passive RFID Tags Will Replace Bar Codes

As the cost of this type of RFID tag or chip continues to go down, it is expected to become as common as bar codes. In fact, many believe they will eventually replace bar codes on products. Technology is being developed that will eventually allow for RFID tags to be roll-printed, like a magazine. This would make the cost of each individual RFID tag almost nothing, making the need for barcode obsolete.

Semi-Passive RFID Tags

As mentioned earlier, semi-passive RFID (Radio Freqency Identification Devices) tags have their own power source, but this power source only powers the microchip and not the radio frequency signal. The antenna is powered in the same that the passive RFID tag receives power. The semi-passive RFID tags have greater sensitivity than passive tags and can therefore be read from much greater distances. Because the battery doesn’t power as much as the active tag battery does, it has a longer life. It can also perform functions that a passive RFID tag cannot perform.

How RFIDs Are Used on Products and in Logistics

The RFID system captures and manages detailed information about items through out the entire supply chain. The system greatly improves supply chain management by providing timely information. This includes information about when items are in storage, when they are in transit, and when they are delivered. The RFID tags or chips allow manufacturers to track the complete production history of each product. This in turn, allows them to have a better understanding of product defects and successes and to have timely information about which products should or should not be produced. Customers of the manufacturers benefit from RFID systems in a number of ways including having a dramatic reduction in out-of-stock items and by only having items that sell well produced and delivered.

RFID How it Works example

The best way to describe how the system works is to describe how an individual company implements the system. An example of a company that uses an RFID system is Wal-Mart. Wal-Mart has RFID readers installed on the store receiving docks that record the arrival of goods that have been shipped with RFID tags. Other RIFD readers are installed in the doorways that lead out of the storage room into the sales area. Wal-Mart then uses sales data from the point of purchase systems and from the RFID data about the number of items brought onto the sales floor to determine which items need to be restocked. This automatically creates a list of items that need to be either picked up from the storage area or shipped from the manufacturers.

Wal-Mart shares the data it collects with its suppliers through an extranet system it has created called the Retail Link. The data is used to improve inventory management because the suppliers and manufacturers know exactly where their products are located and how many need to restocked or produced.

The RFID system has helped Wal-Mart reduce the out-of-stock merchandise in its stores by over 30 percent in the first two years of the systems implementation. The system still has room for improvement, however. Because RFID tags are still relatively expensive, Wal-Mart doesn’t require each item to be tagged rather it uses RFID tags on cases of individual items. The implementation of the RFID tags cost suppliers 25 to 75 cent per case or pallet. This is not substantial when it comes to per pallet cost, but it would be costly if each item where to be RFID tagged. Once the RFID tags become cheap enough Wal-Mart will be able to tag each item and the information will be timelier and more precise. Once the technology is developed for the printable passive RFID tags, it wont be hard for Wal-Mart supplier to afford printing RFID tags on each individual product.

As can be seen by the success of the Wal-Mart example and many other examples not mentioned, RFID tags (Radio Freqency Identification Devices) have great potential in not only logistics but many other areas as well. Only the future can tell how great this potential will be, but one can be sure that they will play a great role in the future and that they will part of everyone’s life in someway. Cargo management will become more efficient and companies will save money, which in turn will save everyone money.