RSS
About RFID Technology
Nowadays, information systems and, in particular, Auto ID systems are a very important part of business. Due to the increasing demands of such systems, the existing solutions based on the marking of objects with bar code labels are insufficient or do not fully meet our expectations. In this case it may be very helpful to use the technology of radio identification of the objects – RFID.
The article presents various available RFID technologies and their general description and example of the application, where the technology works the best. This information should be very useful when selecting the most optimal solution of implementing specific business processes that fully meets our expectations.
RFID Technology
RFID (Radio Frequency Identification) uses radio waves to carry out communication with the transponders keeping information about the identified object. Very often, this technology is called radio barcode (because of the frequent combination of these two technologies - labels with RFID tags inside and printed with a barcode).
The main use of this technology is to track and identify objects marked with RFID tags (transponders). Unlike bar codes, we can carry, almost simultaneously, the reading and writing of information to and from multiple RFID tags. Both read and write of information can be carried out at a distance of up to several meters without the need of direct contact (RFID tag need not be in optical contact with the antenna reader). No need to "see” the antenna reader by the RFID tag greatly expands the possibilities of automatic identification systems.
RFID Tags
Tags consist of at least two parts. The first one is an integrated circuit, implementing functions such as storing and processing information. The second part of the tag is the antenna used to receive and transmit signals. The shape of the antenna can be varied which allows the production of tags with different shapes and sizes. Currently, manufacturers are offering the tags with the possibility of outprint on, plastic cards, blocks or circles of different sizes, or in the form of semi-inlays used for the production of RFID tags. Inlays are the systems with antennas placed between two layers of foil. This solution also allows to apply tags to products already at the stage of production process. The example is the production of cardboard packaging production where the RFID tag is placed between the layers of the cardboard.
 |
| Pic.1 presents the RFID tag sandwiched between two layers of foil, these tags are called inlays. |
There are three types of RFID tags - passive tags, active and semi-passive additionally equipped with a battery. Passive tags do not have their own supply system, therefore, they are characterized by short-range reading. Active tags with their own power supply can help to increase the distance of information reading. The third type of tags are tags that can be described as a hybrid, formed by adding the battery to passive tags except that the "extra" power of tag is only used at the start of communication with the reader and not, as in the case of active tags, on a continuous basis. In addition to division of because of the way of obtaining energy, tags are also divided due to the operating frequency range.
Passive tags can still be further divided according to operating frequency.
Low Frequency RFID tag uses low-frequency band from 125 to 134 kHz.
Main features: reading of tags are possible in a relatively short distance from the antenna (about 40cm) which limits the range of applications. Limitation is the inability to read several tags at one time, and if at the antenna range there is more than one tag, none will be read correctly.
Passive tags can still be further divided according to operating frequency.
Low Frequency RFID tag uses low-frequency band from 125 to 134 kHz.
Main features: reading of tags are possible in a relatively short distance from the antenna (about 40cm) which limits the range of applications. Limitation is the inability to read several tags at one time, and if at the antenna range there is more than one tag, none will be read correctly.
 |
| Pic.2 Plastic card with RFID transponder inside |
Applications:
- Access control systems for premises
- Working time recording systems based on readings at the worker’s entrance and exit from the factory
- Vehicle security system - immobilizer, key card
High Frequency RFID uses high-frequency band of 13.56 MHz.
 |
| Pic.3. – Transponders in the plastic housings are available in various shapes and sizes, they allow the system to work in diverse environments. |
 |
| Pic.4 - RFID tag placed on the PCB, often used to marking an object in its interior at the stage of production. |
 |
| Pic. 5 - One of the smallest RFID tags |
HF tags have a much greater possible distance of reading compared to the LF technology. By using a sufficiently large antenna it is possible to obtain readings from up to 1 m. An additional advantage is the possibility of reading several tags simultaneously when tags are in the field of antennas and they maintain the minimum distance of about 2 cm to each individual tag.
 |
| Pic. 6 - The combination of RFID technology and barcode technology. Tag placed under the printed label. |
Applications:
- Identification and tracking of the lot on the production line (markings of the objects as well as media objects such as baskets, containers)
- Registration of the circulation of documents, books in libraries
- Marking and identification of objects (used in conjunction with a barcode at airports to identify customers' luggage.)
Ultra High Frequency RFID technology can carry a much greater reading distance than HF. In the case of RFID systems in Europe, it is possible to conduct readings even from a distance of about 3m due to the maximum authorized power. In addition to varying the permissible power, also the frequency is different in different parts of the world. The problem of different UHF frequencies was solved with the introduction of the EPC Gen2 standard, readers and tags operating in this standard can communicate with the entire frequency range. This allows to use the UHF RFID technology on a global scale.
The main feature of UHF tag is the largest available reading distance and reading several tags simultaneously within range of the antenna (eg, inventory of pallets, carriers). Another advantage is the ability to conduct the tags’ readings on any orientation relative to the antenna.
Applications:
- Automatic identification of objects
- Batch tracking systems
- Standard GS1 - EPCGlobal - a global electronic product key
 |
| Pic. 7 - Different shapes of UHF RFID tags and labels as inlays. |
 |
| Pic. 8 - UHF RFID tag located under the label. |
The advantages of RFID systems, regardless of the frequency:
- Communication with the identifier does not require the direct optical contact
- Exchange of information takes place fully automatically without operator involvement
- Possible multiple reading and writing of information from the identifier as opposed to information encoded in bar codes on labels
- Wide range of identifiers’ shapes and sizes allows you to choose solutions matched to the needs
- Solutions on a global scale - GS1 EPC Global Standard
