BASIC CONCEPTS OF RFID TECHNOLOGY
Radio frequency identification (RFID) is the wireless or contactless transmission of a digital ID and additional data between an RFID tag and a reader using electromagnetic waves. Tagging physical objects allows businesses, organizations, and consumers to assign a unique digital identity – a digital twin – to seamlessly identify, authenticate, track, sense, and interact with each object.
Unlike other Auto-ID technologies such as optical QR codes, RFID allows tags to be read without line of sight at distances ranging from a few centimeters to over 20 meters or 60 feet, depending on the type of RFID system. Typical examples include reading hundreds of tagged products inside boxes on a pallet with a fixed reader gate mounted behind the door of a dock. Or swiping a handheld reader across store shelves to count inventory in seconds. Or tapping a smartphone on a luxury wallet to verify authenticity and register for a loyalty program.
How does RFID work?
Simply put, an RFID system comprises three components: RFID tags or smart labels; RFID readers (also known as interrogators); and software (also known as middleware) to feed the acquired data into an IT system or the Internet of Things (IoT). Depending on the application requirements, system components need to be carefully selected to enable the desired performance, accuracy, and reliability.
RFID tags and labels
RFID tags come in many different shapes and sizes and are either “passive” or “active.” Typically, they are passive, meaning they don’t require an integrated power source, such as a battery. Passive tags are usually made with an RFID coating and a protective sheath to shield them from physical damage. The coating includes a small silicon microchip that stores the digital identity as well as additional data and is attached to an antenna on a thin substrate such as paper or plastic film (PET). The passive tag’s antenna receives radio waves from the reader and directs them to the microchip, where energy is collected and used to send a radio signal back to the reader.
The coating can be very thin and easily embedded into traditional labels, turning them into smart labels, or embedded into highly durable plastics (Hard Tags) or biocompatible glass (Glass Tags) for extremely harsh environments, or injected into animals.
Types of RFID
RFID systems are grouped into three main radio frequency bands: Low Frequency (LF), High Frequency (HF), and Ultra High Frequency (UHF). These vary depending on the application, maximum reading range, as well as the type of RFID tag and reader used.
Ultra High Frequency (UHF)
UHF RFID systems operate in the frequency range of 860 to 960 MHz. Typical reading distances range from close contact to over 20 meters or 60 feet, enabling a wide range of applications such as inventory and supply chain management, smart manufacturing, airline baggage tracking, sports timing, and more.
Within the frequency spectrum, there are two main regional sub-bands defined by regulatory bodies. The European Telecommunications Standards Institute (ETSI) has defined 865–868 MHz for RFID use, and the Federal Communications Commission (FCC) has chosen 902–928 MHz. Some of our RFID tags and overlays are designated for either FCC or ETSI frequencies, but many newer products support both bands.
Compared to HF and LF, UHF systems support longer reading ranges and allow for cost-effective overlays and tags in a variety of sizes and shapes, as well as fast reading of bulk items, but are susceptible to radio interference from metals or conductive materials or liquids.
High Frequency (HF) and Near Field Communication (NFC)
RFID HF and NFC systems operate in the 13.56 MHz frequency band and allow reading ranges from close contact to 50 cm or 20 inches. Typical applications include library media management, manufacturing automation, gambling chip management, ID cards, contactless payments with NFC payment cards or smartphone applications, and consumer engagement. While HF cards require a special reader, NFC cards can be read by almost any smartphone at a distance of a few centimeters.
With billions of NFC-enabled smartphones on the market today and more and more consumers becoming familiar with contactless payments, there is a huge opportunity to leverage NFC tags for consumer interactions and other new consumer-centric applications.
Low frequency (LF)
Most LF systems operate in the frequency range of 125–134 kHz and allow reading ranges up to 10 cm or 4 inches. Typical application areas include animal identification, access control, vehicle access, and environments with high concentrations of liquids and metals.
Compared to UHF and HF, LF systems have lower data transmission speeds and reading ranges, while the low frequency supports applications in challenging environments.
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