Selecting the right RFID tag is not easy!
It requires a full understanding of the relationship between tags, read/write devices, systems, as well as the purpose behind the RFID tag application. RFID tag performance is affected by the working environment.
Certain factors should be considered when selecting proper RFID tags, such as the tag type, operating frequency, object material on which the tag will be attached, installation, reading range, reading rate, tag specification, working environment, variable data processing, cost, …etc.
1. Frequency
Passive RFID tags have three kinds of frequencies: LF, HF and UHF. Selecting the right frequency depends on certain factors such as the reading range requirements, data reading rate, security level, cost, …etc. Applications like access control and payment systems require a short reading range, and typically use HF tags. UHF tags are ideal for applications requiring a long reading range.
- LF (Low Frequency): In the case of special application environments and if there is no requirement for reading distance, LF can be considered. An example would be animal management. LF transfers data slowly, has a small and limited storage memory, poor flexibility, weak security, is often unwritable and costs more due to the hundreds of coil wires. It is not easy to make flexible LF tags, which is why the market shares are decreasing.
- HF (High Frequency): Readable and writable. HF is selected for applications with more capacity and a high encryption level, such as payment, ticketing, security access control, membership management and identification applications.
- UHF (Ultra High Frequency): Readable and writable with a long reading distance of up to 10 meters. Anti-collision UHF provides bulk RAIN UHF tag reading, has fast transmission speeds, and can read 1,000 tags (EPC C1G2) all at once. It has a linear and circular polarization antenna design, which can meet the requirements of different applications, has a low cost, is easy to operate, and has a wide range of applications. The state-of-the-art IoT has already adopted UHF technology in areas such as the supply chain, warehouse management applications, logistics, retail and other managements.
2. Environmental Factors
Environmental conditions are the main considerations for RFID tag selection. The environmental conditions that affect the performance of the tags are mainly temperature, humidity, indoor or outdoor usage, compression and anti-collision, metal, oil, acid, and alkaline chemicals.
For example, the label embedded in the product may encounter high temperatures and heavy pressure during a product manufacturing process. For outdoor applications, the influence of UV, rain, and temperature on label life should be considered.
3. Tag Type
Tag types are chosen according to the reading range, application environment, cost, size, material, installation, and application in special industries.
The RFID tag encapsulations are available in PVC, PET, PPS, nylon, ABS, ceramic, silicone, inlay, RF-4, and paper.
Flexible RFID tag: If you need long reading distances for normal applications and storage environments, cost-wise, PET or flexible paper UHF tags are generally the best choice.
When involving metal and harsh working environments, such as oil, chemicals, extremely high and low temperatures, rigid hard-enclosed plastic housing RFID tags, ceramic RFID tags, FR4 PCB RAIN tags, and RFID cable tie seal tags are the best selection.
Foam on-metal UHF tags are an economical metal-resistant RFID tag solution.
LF and HF hard laminated PVC RFID tags are normally used for common application environments and have cost-effective requirements. There are also special applications such as animal management, waste management, the laundry industry, pharmaceuticals, and cold chain management.
4. Reading Direction
Tag performance is affected by the orientation of the antenna of the reading device. Optimal tag orientation is when the plane of the tag and the plane of the antenna are parallel to each other. In this direction, the tag will receive maximum power. As the tag rotates, it presents a smaller effective area for incoming radio waves, therefore, less power is collected. The tag reading range decreases as the collection power decreases.
Most passive UHF tags have a dipole antenna, with zero points at the north and south poles. Such tags cannot be read when the magnetic pole axis on the tag antenna is perpendicular to the plane of the interrogator antenna. The best effect appears when the RFID tag antenna coil is parallel to the coil of the reader.
5. RFID Tag Placement
The placement of the RFID tag on the object will affect the tag’s performance. Especially obvious are the effects of moisture and metal on tag performance. To counter these factors, has special solutions when designing and selecting tags for products such as wine, shampoo, beverages, a variety of drugs in liquid form, and edible liquid substances in bottles.
To read a UHF label attached to a bottle containing liquid contents, there must be a certain amount of space between the label and the liquid bottle. The RFID label can be designed according to the actual bottle or container so that its antenna is always positioned away from the liquid, such as the HUAYUAN RFID Flag Tag.
6. RFID Tag Installation
The installation methods of RFID tags include: self-adhesives, screws, rivets, hanging, and magnetic adsorption. This depends on the actual situation and respective requirements, whether it needs to be permanently fixed or transferable.
For the self-adhesive tags, it is also necessary to know the material of the object which the tag will be stuck onto in order to determine what type of glue to use.
The installation of RFID anti-metal tags is possible using rivets, screws or magnets.
HUAYUAN Electronic has been focusing on RFID R&D since 1995, with extensive experience and plenty of successful cases with clients.
