|
Radio Frequency Identification (RFID) uses transponders usually called Tags that have an Antenna and an ASIC (Application Specific Integrated Circuit) with memory. Its history can be traced back to 'friend or foe' transponders (remote transmitter receiver device) fitted to aircraft in World War II, through scientific work in the 70's, to animal ID tags introduced in the USA and UK in the 80's.
Growth in the 90's was primarily in two fields, access control (contact less ID card) and car security. Many car keys contain an RFID Tag that is read by an Antenna in the steering column and used to immobilise the vehicle.
The 'chipping of goods initiative' scheme has become one of the best-known applications of RFID. Others include automatic road toll collection, ski lift passes, timing in races such as the London Marathon (tags fitted into shoes), electronic article surveillance (EAS - anti-theft in shops), asset management, pallet tracking and labelling for airline baggage, retail logistics and the supply chain.
Radio frequency identification (RFID) technology assures to improve the efficiency of the supply chain, providing a much better and far more intelligent and accurate way to track goods and assets throughout the chain.
How Does An RFID System Work?
RFID uses radio waves to communicate information from a 'Tag' to a 'Reader' via an 'Antenna'. The tag can be described as a small radio transmitter. Using the reader (an electronic device that communicates with the tag) and antenna it is possible to read the data stored on the tag. The data can consist of serial numbers, security and or products codes. When the reader has read the tag data the information is then passed on to a host system.
There Are Generally Three Components To Any RFID System:
Types of RFID Tags
An RFID tag can come in a wide variety of shapes and sizes. From as small as a pencil lead for animal tracking, credit card sized for access control applications, in 'smart label' forms or even worn as a wrist band. Some of the anti theft plastic tags that are found in most retail outlets are a type of RFID tag.
An RFID tag can be 'Active' or 'Passive' (with or without a battery). All Passive Tags are powered by the electromagnetic field generated by the reader whilst communicating with the tag. The 'Active' tag is powered by a long life lithium cell and can be activated by a transmitted RF field generated by the reader, or data can be transmitted at set timed intervals.
RFID vs. Barcodes
Uniquely identifying products and assets in real time will provide much greater productivity and save on labour costs with improved accuracy. Manually locating and scanning bar codes that can be easily damaged and tampered with can be costly and time consuming.
RFID tags are much more durable and reusable than bar codes making them a reliable and cost effective solution especially for tracking reusable assets like containers, cases and pallets. For products with higher values and margins that need tracking, tracing, security, and authentication, tagging is far more favourable and reliable than bar coding.
RFID Tags have many advantages:
Glossary of RFID Technology Terms
Active Tag |
Any tag that operates with a battery. However, some tags go to sleep when they are not in an RF field, these are sometimes referred to as Semi-Passive tags. |
Passive Tags |
These do not have batteries, they get their transmit power by soaking up energy from an RF field to charge an onboard capacitor. |
Read Only |
These tags have a unique factory programmed number, which cannot be changed. |
Read Write |
The memory section of these tags is split into blocks, each block can be programmed via the reader without a physical link. |
WORM |
Write Once Read Many, the tag can be programmed once with customer information this is then fixed. |
Anti-Collision |
Many tags can be read in a field at any one time. |
Reader/Decoder |
This is the unit that reads the tag data and allows communication with a host system. |
Antenna |
This is used to generate the RF field. |
Low Frequency Tag |
This is a tag operating typically between 125kHz and 134kHz. A typical read range for these tags can be up to 1m. |
High Frequency Tag |
Operating at 13.56MHz. A printed antenna for the tag allows price to be low depending on volume. Most are Read Write and have anti-collision with a read range of up to 1m. |
Active UHF Tags |
Strictly speaking these are not tags but low power radio systems operating within unlicensed radio bands i.e. 433MHz (car plips) and 868MHz and are battery powered. |
Passive UHF Tags |
The latest range of low cost high performance passive tags. These operate as true radio transmitters rather than inductive coupled devices such as the 125kHz 13.56MHz devices. |
Microwave Tags |
UHF/SHF tags are very directional. |
|
Solutions
