RFID (Radio Frequency Identification) systems are ideal for keeping track of and managing any asset, from vehicles on an assembly production line; stock in a warehouse; livestock; to books in libraries. They can also be used for access control, with employees carrying RFID identity cards to trigger the opening of entry doors. A basic RFID system consists of both hardware and software components. There are three hardware components of an RFID system: tag, reader and host system.
RFID Host System
A host system is a system that manages the flow of data between the RFID readers and tags. This may have a complex structure, where different readers are located across different locations and data flows to the host computer through LANs or the Internet.
Hand Held Reader
A RFID reader can be fixed or hand held and is a device that activates the tag and retrieves the information stored in its Integrated Circuit. A RFID reader sends and receives signals with the help of the reader antenna. The reader which is also known as an interrogator, is essentially a bridge between the RFID host system and the reader antenna
RFID Tags are available in many shapes, sizes and frequencies. The tag is also referred to as a transponder and can be attached to or embedded into an item providing a means to track and manage supply-chain and identification details such as attributes, source, destination and route for each tagged item. The tag IC has a basic memory where data like the UID (Unique Identifier) is stored. The basic components of an RFID tag are:
- The integrated circuit (IC): A microchip that commonly stores data. The data stored in the IC can be read several times by the reader.
- The tag antenna: A component that detects the signal from the reader’s antenna. The performance of the tag antenna depends on the distance between the reader antenna and the RFID tag.
The basic types of RFID tags are classified as read / write and read only. When a read / write tag is within the reading range of the reader, you can edit, add or re-write the stored data on the tag. A read-only tag permits you to read the stored data but not edit it.
RFID tags and Inlays consist of three components: a chip, an antenna and a substrate. RFID tags are manufactured in different shapes and sizes depending on the type of application in which they are used.
RFID operates tags can either be Passive (no internal power source), Semi-Passive (passive but includes a battery) and Active which only operate with a battery.
Active Tags: These tags have a longer read range and larger memories than passive tags and usually operate at 455 MHz, 2.45 GHz, or 5.8 GHz frequencies. Typical read range is from 20 to 100m.
Passive Tags: Passive tags have no internal power supply and are instead activated by the reader. Passive tags have read distances ranging from 2mm to 5m depending on the frequency of individual tags as well as the reader and the working environment. Passive tags can operate at low frequency (LF), high frequency (HF) and ultra-high frequency (UHF).
Semi-Passive Tags: Semi-passive tags are an intermediate type of tags that lie between the active and passive tags. They are also called battery-assisted passive tags (BAP).
The software components of an RFID system can differ depending on the system and application requirements.
RFID middleware: Middleware is the software component that links the RFID hardware to the host application software.
Host application: Software that receives and processes data – sent from the tag – through the reader and the RFID middleware software.
A barcode is data represented either as a 1D (linear) or 2D (Data Matrix) image. Barcodes are usually used to encode a serial number or stock keeping unit (SKU) number and identify a class, or type of product rather than identifying a single unit.
RFID vs Barcodes:
- Storage capacity between 128 bytes and 8 kilobytes
- No line of sight or contact required
- Enhanced data security (authentication and encrypted data transfer)
- Can operate in harsh, dirty and humid environments
- Several tags can be read simultaneously
- Read / write functionality (re programmable)
- Storage capacity of 100 bytes
- Require visual contact between scanner and barcode
- No guarantee of security to data. Any scanner can read any barcode.
- Cannot be read when dirty or heavily scratched.
- Scanner can read only one barcode at a time.
- Cannot reprogram the contents of a barcode.
Benefits of RFID
In addition to overcoming the limitations of barcodes, the use of RFID has the following benefits:
- Serialization (unique identification)
- Reduced human intervention
- Better time management
- Real-time information