RFID technology basics

Radio Frequency Identification (RFID) is the wireless or contactless transfer of a digital ID and additional data between an RFID tag and a reader by means of electromagnetic waves. Tagging of physical objects allows businesses, organizations and consumers to assign a unique digital identity -- a digital twin -- to identify, authenticate, track, sense and engage with each object seamlessly.

In contrast to other Auto-ID technologies like optical QR codes, RFID allows tags to be read without a line of sight at a distance of a few centimeters to more than 20 meters or 60 feet, depending on the type of RFID system. Typical examples would be reading hundreds of tagged products inside boxes on a pallet with a fixed reader gate mounted behind the door of a shipping dock. Or swiping a handheld reader over store racks and shelves to count inventory within seconds. Or tapping a smartphone on a luxury purse to verify authenticity and sign up to a loyalty program.

How does RFID work?

Simply put, RFID systems consist of three components: RFID tags or intelligent labels; RFID readers (also called interrogators); and software (also called middleware) to feed the captured data into IT systems or the Internet of Things (IoT). Depending on application requirements, the system components need to be chosen carefully to allow the desired performance, accuracy and reliability.

RFID tags and labels

RFID tags come in a variety of shapes and sizes and are either “passive” or “active”. Most commonly they are passive, meaning they don’t need an integrated energy supply, for example a battery. Passive tags are typically made of an RFID inlay and an enclosure for protection against physical damage. Inlays consist of a small silicon microchip which stores the digital identity as well as additional data and is attached to an antenna on a thin substrate such as paper or plastic (PET) film. The antenna of a passive tag receives the radio waves from the reader and directs them to the microchip, where the energy is harvested and utilized to send back radio signals to the reader.

Inlays can be very thin and easily embedded into traditional labels, turning them into intelligent labels, or embedded into very robust plastic (Hard Tags) or biocompatible glass (Glass Tags) for extremely harsh environments or injection into animals.

Types of RFID

RFID systems are grouped into three main radio frequency ranges: Low Frequency (LF), High Frequency (HF), and Ultra-High Frequency (UHF). They differ by application, maximum read range, as well as type of RFID tags and readers utilized.

Ultra-High Frequency (UHF)

UHF RFID systems operate in a frequency range between 860 and 960 MHz. Typical reading distances are from near contact to more than 20 meters or 60 feet, enabling a broad range of applications such as inventory and supply-chain management, smart manufacturing, aviation baggage tracking, sports timing and many more.

Within the frequency range there are two main regional sub-bands defined by regulatory agencies. The European Telecommunications Standards Institute (ETSI) has defined 865 - 868 MHz for RFID usage and the Federal Communications Commission (FCC) has chosen 902 - 928 MHz. Some of our RFID tags and inlays are specified for either FCC or ETSI frequencies, but many of the newer products support both bands.

Compared to HF and LF, UHF systems support a longer read range, and enable cost-efficient inlays and tags in a broad variety of sizes and shapes as well as fast reading of bulk items, but are more prone to radio wave interference from metallic or conductive material or liquids.

High Frequency (HF) and Near-Field Communication (NFC)

HF and NFC RFID systems operate in a frequency band at 13.56 MHz and allow read ranges from near contact to 50 centimeters or 20 inches. Typical applications are library media management, manufacturing automation, gambling chip management, ID cards, contactless payment with NFC payment cards or smartphone apps, and consumer engagement. While HF tags need special readers, NFC tags can be read with almost any smartphone at a distance of a few centimeters.

As billions of NFC-enabled smartphones are in markets today and more consumers are getting used to contactless payment, there is a large opportunity to leverage NFC tags for consumer engagement and other new consumer-centric applications.

Low Frequency (LF)

Most LF systems operate in a frequency band from 125 - 134 kHz and allow read ranges of up to 10 centimeters or 4 inches. Typical application areas include animal identification, access control, car access, and environments with high densities of liquids and metals.

Compared to UHF and HF, the data transmission rates and read distances of LF systems are lower, while the low frequency supports applications in difficult environments.