What is an RFID Tag

ZBR2000 RFID Inlays

RFID tags consist of an integrated circuit (IC) attached to an antenna typically a small coil of wires plus some protective packaging (like a plastic card) as determined by the application requirements. Tags also sometimes are called 'transponders', and sometimes are called inlays, although technically an inlay is a tag mounted on a substrate that is ready to be converted into a smart label.

RFID tags can come in many forms and sizes. Some can be as small as a grain of rice. Data is stored in the IC and transmitted through the antenna to a reader. RFID tags are either (no battery) or (self-powered by a battery). Tags also can be read-only (stored data can be read but not changed), read/write (stored data can be altered or rewritten), or a combination, in which some data is permanently stored while other memory is left accessible for later encoding and updates.

A tag power source can be passive, semi-passive and active RFID tags are designed to function on specific frequencies or frequency ranges RFID tags come in many form factors such as labels, wristbands, buttons or embedded into items.

How Do Rfid Tags Work

RFID Tags contain electronically-stored information that acts as a label for object identification. Tags identify, categorize and track specific assets. RFID tags contain more information and data capacity as compared to barcodes. Unlike barcodes, in an RFID system, many tags are read simultaneously and data is read from and written to a tag. You can categorize RFID tags in different ways by power source, frequency and form factor. In order to function, all RFID tags need power to energize the chip and to transmit and receive data. The way the tag receives its power determines whether it is passive, semi-passive or active.

The majority of passive tags use EEPROM memory. Some are laser programmed at the silicon level. Many active tags utilize battery-backed SRAM. Passive tags (non-battery) typically have anywhere from 64 bits to 1 kilobyte of nonvolatile memory.

Active tags, such as those used in military tags, have memories as high as 128 kilobytes.

The typical operating temperature for an RFID inlay (tag) found in most smart labels is between -25º C and 70º C. Storage temperature typically is between -40º C and 85º C. These values will vary from manufacturer to manufacturer and will depend on the tag components. There are industrial tags available in the market that will withstand temperatures as high as 250º C, which could, for example, stand up to heat sterilization requirements for medical items.

What Are Rfid Tags Used For

RFID tags can be used to track livestock, medication, groceries or patients in a hospital. They are able to follow an item in an assembly line process or automatically collect tolls as cars pass by a reader on a road.

Zebra RFID Reader

How to Read Rfid Tags

An RFID Reader is a key component of an RFID Solution. Readers activate a tag within its range and then collects the tag data. Readers also have the capability to write or encode an RFID tag as well. While a reader can process numerous tags at one time, it can recognize each individual tag and can prioritize of all the collected data. Readers use algorithms and filtering of tag data to read all of the incoming data and can also isolate particular tags based on certain logic and its importance to a particular process. For example, a reader can process all tags in a given area but has the ability to focus on a particular tag in order to facilitating finding or locating that particular item more efficiently.

There are different types of RFID Reader including fixed and passive UHF which come in a variety of shapes, sizes and price range. Knowing the environment and application will help narrow down the choices. For example, a small retail stockroom may use a fixed reader at the transition door to read products moving in and out of the backroom whereas a shipping or receiving dock would use an industrial fixed reader in a dock door portal installation to read pallets coming on and off of a truck. A large store selling floor may use a ceiling mountable fixed reader to cover the selling floor. Fixed readers also incorporate antennas as part of the solution. It is the antenna that emits the power and captures the data back from the tag to pass back to the reader.

Handheld readers are typical when it is necessary to read the asset in place, they perform the same function as fixed readers however they allow for flexibility in the workplace. Handheld readers by nature go to the actual asset, they perform in wider ranges of environment and are a cost-effective solution for RFID reading.

Handhelds also offer both RFID and barcode reading capabilities and can be leveraged to run current standard applications as well as specific RFID functions. Handhelds, like fixed readers also come in different form factors both integrated with a mobile terminal as well as the sled variety that can be paired with a mobile computer of a customer’s choice.

How Do Passive Rfid Tags Work

RFID tags are available in many form factors, the core component of an RFID tag is the inlay. The inlay can have an adhesive applied, be layered between paper or encapsulated in an hardened RF friendly material which protects the inlay in harsh environments.

In a passive RFID Tag, some type of substrate holds the Integrated Circuit, strap and antenna together. The integrated circuit is what contains the information on the tag and is very small. The tag antenna is the conducive element that enables the tag to send and receive data to and from the reader.

Smart Labels are a passive RFID Tag and consist of an RFID tag layered between a printable stock and adhesive backing material. Smart labels supports various systems. In many processes, the barcode or 2D barcode is the key means for identification in short distance.

Smart labels become smart through the technology of plain text, optical character recognition or OCR and RFID combined in one label. Smart labels provide flexibility in a process such as the ability to manually read a label when it is pertinent for human intervention in a process. As well as the flexibility to use barcode scanners such as at a register when handling a customer transaction but still utilizing RFID for inventory management in areas like receiving docks to process inbound pallets of inventory.

What Is the Difference Between Epc’s Gen 1 Tags and Gen 2 Tags?

With regard to Generation 1, there are Class 0 and Class 1 specifications for tags in the UHF band. Class 0 was originated as a protocol by Matrics Technology Systems (acquired by Symbol Technologies) and Class 1 was originated as a protocol by Alien Technologies. Class 0 has been defined by EPC global as a read-only device. Class 1 is defined in the EPC global specification as a tag that is one-time programable. In practice, the products that are available from Alien Technologies are reprogramable. And Matrics/Symbol has released "Class 0+products", which are based on the same protocol as the Class 0 device, but are, in fact, fully re-writeable.

With reference to Generation 2, Class 1 (Class 0 was dropped) standards were ratified at the end of 2004 as a response to the limitations of the Generation 1 standards. Gen 2 provides expanded data functionality and better performance, is designed to support EPC codes up to 256 bits long and has the provision for extra data to be carried in the tag based on a single RFID protocol. In addition, G2 tags should be comparable regarding radio frequencies (from 860 MHz to 960 MHz) globally, allowing tags to work consistently in different countries under differing emissions standards. Tags must be able to understand three different approved modulation schemes as well as be able to transmit at several different speeds or data rates. In addition, Gen 2 includes a method to support dense-interrogator channelized signaling (also called "dense reader mode"), which attempts to reduce interference among readers to make it less likely that reader signals will impede tag signals.

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