Active tag: An RFID tag that has a battery that powers the circuitry and transmits the signal to a reader. Active tags can be read from 100 feet away or more and are used for tracking expensive items over long ranges.
Antenna: The element built into both RFID readers and tags that radiates and receives radio energy.
Automatic identification (also called automatic data capture): The ability to collect and enter data directly into computer systems without human involvement through technologies such as barcodes, biometrics, RFID and voice recognition.
Backscatter: A method of communication where tags reflect back a portion of the radio waves that are emitted by the reader to transmit tag data to the reader.
Battery-assisted tag: These RFID tags contain batteries that provide direct power on the tag itself to increase read range (sometimes called “semi-passive RFID tags.”)
Circular-polarized antenna: This omnidirectional UHF reader antenna emits radio waves in a circular pattern and is designed to easily capture RFID tags that are presented in different orientations.13
Contactless smart card: A credit or loyalty card that contains an RFID chip that can automatically transmit information to a reader — no ‘swiping’ required. Such cards can speed checkout, providing consumers with more convenience.
Chipless RFID tag: An RFID tag without an integrated microchip. Materials in the tag reflect back a portion of the radio waves beamed at them from the reader. The waveforms are utilized much like a fingerprint to identify the object that is tagged. Although chipless tags are inexpensive, they are not useful in the supply chain since they cannot transmit a unique serial number that can be stored in a database.
Closed-loop systems: RFID tracking systems set up within a company, where there is no data sharing with other companies required to enable the application. One example is a railroad that issues its own RFID‑enabled tickets.
Die: The silicon block onto which circuits have been etched.
Electromagnetic interference (EMI): Interference caused when the radio waves of one device distort the waves of another. Cells phones, wireless computers and even robots in factories can produce radio waves that interfere with RFID tags.
Electronic article surveillance (EAS): Simple electronic tags that can be turned on or off. When an item is purchased or borrowed, the tag is turned off. When the item passes a gate with a tag that hasn’t been deactivated, an alarm sounds, helping prevent theft.
Electronic Product Code (EPC): A 96-bit code created by the Auto-ID Center that contains a unique number that identifies a specific item in the supply chain. The code contains digits that identify the manufacturer, product category and the individual item. It is backed by the United Code Council and EAN International, the two main bodies that oversee barcode standards.
EPCglobal: The non-profit organization that manages standards and numbering schemes associated with EPC and the successor organization to the Auto ID Center. EPCglobal is a membership-driven organization and is a subsidiary of the
European Article Numbering (EAN): The barcode standard used throughout Europe, Asia and South America. It is administered by EAN International.
Excite: The reader is said to “excite” a passive tag when the reader transmits RF energy to wake up the tag and enable it to transmit back.
Frequency: The number of repetitions of a complete wave within one second. 1 Hz equals one complete waveform in one second. 1 KHz equals 1,000 waves in a second.
GTAG (Global Tag): A standardization initiative of the Uniform Code Council (UCC) and the European Article Numbering Association (EAN) for asset tracking and logistics based on radio frequency identification (RFID). The GTAG initiative is supported by NXP, Intermec, and Gemplus — three major RFID tag manufacturers.
GTIN (Global Trade Item Number): A GTIN is a GS1 identification key that enables global identification of an item anywhere in the supply chain. No matter in the supply chain an item may be — from manufacturer to distributor to retail store to end consumer — a scan of the GTIN enables any partner in a given supply chain to accurately identify the product and obtain pricing. The result is highly efficient ordering and invoicing across the supply chain.
Harvesting: A term that describes how passive tags gather energy from an RFID reader antenna.
High-frequency (HF) tags: HF tags typically operate at 13.56 MHz and can be read from about 10 feet away. They transmit data faster, but consume more power than low-frequency tags.
Integrated circuit (IC): A microelectronic semiconductor device comprising many interconnected transistors and other components. Most RFID tags have ICs.
Interference: Anything that prevents radio waves from traveling between a tag and reader correctly and causes the tag to be read incorrectly. Can be caused by other radio signals or by some physical objects metals and liquids that absorb or reflect the radio signals.
Interrogator: See RFID reader.
Linear-polarized antenna: A UHF antenna where the radio energy is focused in a narrow beam to increase read distance and enable the signal to penetrate dense materials. Unlike circular-polarized antennas, the linear-polarized antenna requires tags to be aligned with reader.
Low-frequency (LF): The range of frequencies between approximately 30 kHz to 300 kHz. LF tags typically operate at either 125 kHz or 134 kHz. These tags can be read from less than three feet away and have a slow rate of data transfer, but can withstand more interference than the typical UHF tag. 14
Memory: The amount of data that can be stored on a tag.
Microwave tags: Radio frequency tags that operate at 5.8 GHz. They have very high transfer rates and can be read from as far away as 30 feet, but they use a lot of power and are expensive.
Middleware: Computer software that connects software components or applications. It is used most often to support complex, distributed applications based on XML, SOAP, Web services and service orientated architecture (SOA). Middleware can include web servers, application servers and content management systems.
Nominal range: The read range at which a tag can be read reliably.
Object Name Service (ONS): An Auto-ID Center system that allows the look up of unique Electronic Product Codes (EPC). ONS is similar to the Domain Name Service, which points computers to sites on the Internet.
Orientation: Refers to the relative position of the tag to the reader. If tags are aligned (or ‘oriented’) with the reader, read ranges are generally longer.
Passive tag: An RFID tag without a battery. When radio waves from the reader reach the chip’s antenna, it creates a magnetic field. The tag draws power from the field and is able to send back information stored on the chip.
Power level: The amount of RF energy radiated from a reader or an active tag. The higher the power output, the longer the read range, but most governments regulate power levels to avoid interference with other devices.
Read rate: The maximum rate at which data can be read from a tag expressed in bits or bytes per second.
Reader (also called an interrogator): The reader communicates with the RFID tag via radio waves and passes the information in digital form to a computer system.
Read range: The distance from which a reader can communicate with a tag. Active tags have a longer read range than passive tags because they use a battery to transmit signals to the reader. With passive tags, the read range is influenced by frequency, reader output power, antenna design and method by which the tag is powered. Low frequency tags use inductive coupling (see above), which requires the tag to be within a few feet of the reader.
RFID Chip: The small computer, almost as small as a grain of sand, which is the heart of every RFID tag. The two main parts of an RFID tag are the chip and the antenna.
RFID tag: A microchip attached to an antenna that picks up signals from and sends signals to a reader. The tag contains a unique serial number, but may have other information, such as a customer’s account number. Tags come in many forms, such as smart labels affixed to boxes; smart cards and key-chain wands for purchase transactions; and a box that is affixed to your windshield to enable you to pay tolls without stopping. RFID tags can be active, passive or semi-passive.
Semi-passive tag: Similar to active tags, but the battery is used to run the microchip’s circuitry and not to communicate with the reader. Some semi-passive tags sleep until they are woken up by a signal from the reader, which conserves battery life.
Smart label: A label that contains an integrated RFID tag that is considered “smart” since it can store information, such as a unique serial number, and communicate with a reader.
Tag: See RFID Tag.
Transponder: A radio transmitter-receiver that is activated when it receives a predetermined signal. RFID tags are sometimes referred to as transponders.
Ultra-high frequency (UHF): Typically, tags that operate between 866 MHz to 930 MHz. UHF tags can transmit information faster and farther than high- and low-frequency tags. But radio waves don’t pass through items with high water content, such as fruit, at these frequencies. UHF tags are also more expensive than low-frequency tags, and they use more power.
UHF Generation 2: The current EPC standard for factory-programmed tags.
Uniform Code Council (UCC): The nonprofit organization that oversees the Uniform Product Code, the barcode standard used in North America.
Uniform Product Code (UPC): The barcode standard used in North America. It is administered by the Uniform Code Council.
Write Range: The distance where a tag is written by a reader/writer without any object between the tag and the reader/writer. Normally, write range is lower than read range.
Write rate: The rate at which information is transferred to a tag, written into the tag’s memory and verified as being correct.