RFID Tutorial: Basics, Frequencies, Network, and Applications

This tutorial covers the fundamentals of RFID (Radio Frequency Identification), including terminology, frequencies, network architecture, cost considerations, applications, and vendors.

RFID Terminology

• RFID Tag: Used to identify people, devices, or objects. Two main types exist:

  • Passive Tags: Reflect radio waves transmitted by an RFID reader, allowing the reader to determine the tag’s location. Typically have a range of 3-5 meters and do not have an internal power source. They rely on the power of the active tag, which passive tags obtain wirelessly using E-M waves.
  • Active Tags: Send radio waves to the RFID reader, actively informing it of their location. Have a longer range (up to 100 meters) and contain their own power source.

• Class 1 Generation 2 Tags: Are backward compatible to generation 1 class 0 & class 1 RFID tags. RFID tags can be divided into five classes as shown in the following table:

• RFID Reader: Primarily active devices that read information transmitted or reflected by RFID tags. They are typically interfaced with a computer system.

What is RFID?

RFID (Radio Frequency Identification) utilizes radio frequency waves for communication. The common method used to identify objects/persons is through serial numbers assigned to each tag. Additional information can be customized as needed.

An RFID tag typically consists of a small microchip and an antenna. The tags communicate with the reader via the antenna, and the reader converts the reflected or transmitted information into usable digital data for processing by software on a computer. RFID commonly operates in the UHF frequency range.

RFID Frequencies

RFID networks operate primarily on three main frequency bands: LF (Low Frequency), HF (High Frequency), and UHF (Ultra-High Frequency).

RFID Network

Factors that influence the design of an RFID network include coverage area and the number of objects/people being tracked.

Here’s an example of RFID used for school tracking:

RFID can be used for student attendance management and to notify parents/authorities of student movement in real-time via SMS or email. Each student is provided with an RFID badge containing their photo and other vital information.

Image of an RFID network setup.

RFID tags on student badges communicate with RFID readers. These readers, equipped with TCP/IP, are connected to the LAN, which then connects to a server. The server interfaces with an SMS gateway to send notifications to authorized personnel. RFID readers are strategically installed at entry and exit points of the school premises.

When a student enters or leaves, the RFID reader captures the tag information and sends the data to the server for validation. Once validated, an SMS or email is generated and sent to the registered mobile number or email address.

Factors in Determining RFID Network

System integrators or RFID suppliers consider the following factors when addressing RFID requirements:

1. Area Size: Determines whether active or passive RFID tags are more suitable.
2. Tracking Locations: Decides RFID reader placement and the required number of readers.
3. Number of Objects/People: Helps design the database requirements for the GUI software connected to the RFID reader.
4. Tag Embedding Method: Determines how tags will be attached (e.g., ID card, wristband, stitched into uniform).

RFID Applications

• Production line management
• Access control
• Patient ID management
• Logistics and warehouse management
• Asset tracking
• Parking management

RFID Cost

RFID passive tags typically cost less than a dollar, while active tags cost around $25. RFID readers range from$500 to $700, depending on features.

RFID Vendors

RFID vendors/manufacturers supply RFID tags and RFID readers for various applications.

RFID Standards

RFID Class-1 Generation-2 specifications can be downloaded from this link: UHF Class 1 Gen 2 Standard v. 2.0.0