LF RFID Tag
Low frequency RFID tags work well on objects containing water and have a short range. These types of tags are often used in access control, livestock tracking and other applications.
The simulation results demonstrate that the designed tags perform well on a wide range of substrate materials and thicknesses. Moreover, the tags that were designed for NMP operation outperformed their MP counterparts.
Frequency
LF RFID tags operate at frequencies between 30 KHz and 300 KHz. They typically use 125 KHz or 134 KHz and work at a much slower data transfer LF RFID Tag rate than higher frequencies. However, they are more resistant to interference from electromagnetic environments than UHF.
Unlike other forms of passive RFID tags, LF RFID tags are powered by inductive coupling between the tag antenna and reader. The magnetic fields of the reader coil induce voltages in the tag antenna, similar to a transformer. This voltage provides power for the tag to transmit a short identifying transmission (called a beacon) at infrequent intervals. This approach conserves battery power, which may be limited by the application environment or regulatory requirements.
LF RFID tags are available in a variety of form factors, including cards, glass tubes, coils and plastic bricks. LF cards are often used for access control, while LF glass tubes are commonly used in animal tracking and asset identification. LF coils are often embedded into assets for industrial applications like inventory management and work in process management. LF brick tags are specially designed for automotive applications as vehicle immobilizers. They are also a good choice for applications that require a small footprint, as they excel when mounted in or on metal. This type of RFID tag is a key component in systems for tracking valuable assets, such as containers and trailers.
Antennas
LF RFID tags use passive transponders that do not actively radiate radio waves until they receive a reader signal. They are used in library books, credit cards and smart keys. LF tags are also used in animal tracking and point-of-sale applications such as Mobil/Exxon SpeedPass.
HF RFID interrogators use magnetic flux to power and communicate with the tag. The magnetic flux is omnidirectional and covers the surrounding area evenly, so it can reach multiple tag locations without interfering with other nearby devices. This allows HF RFID systems to be used in warehouses, on retail shelves and in manufacturing processes.
When selecting an RFID antenna, it is important to consider the gain, opening angle and beam width pattern of the antenna. A wider wave has a lower gain than a narrower one, but can cover more ground in a single beam. The polarization of the antenna is also important. Circularly polarized antennas can be rotated to different orientations, but they have a shorter read range than linearly polarized ones.
UHF RFID tags offer longer read ranges and better performance than LF RFID tags, but are more expensive. They can be read at a distance of up to 14 metres, and are ideal for indoor applications such as warehouses or industrial processing. They are also ideal for transportation and supply chain management applications, including truck and trailer tracking and inventory control.
Read Range
LF RFID tags are passive and require no battery. Their operation is based on inductive coupling, where magnetic fields from the reader antenna induce voltages in the tag smart card supplier antenna that power it and send it identification information. Because of their shorter wavelength and lower operating frequency, they are less susceptible to interference from metals and liquids than higher-frequency tags.
The LF band operates at 30 kHz to 300 kHz. LF tags use a copper coil with many windings that are affixed to a metallic core for transmitting and receiving electromagnetic waves. The alternating magnetic field from the reader’s antenna induces voltage in the tag antenna, much like primary and secondary windings on a transformer. The read range is typically limited to a few centimeters and depends on the size of the reader and antenna.
LF is a good option for tracking inventory of objects that are affixed to or embedded in metal or other materials. Unlike HF and UHF tags, which emit strong signals that can penetrate metal layers, LF waves can only be detected when the tag is close to the exciter. LF tags also transmit very briefly (known as beacons) at infrequent intervals, conserving battery power. This method of location tracking is known as Real Time Location Systems (RTLS). LF tags are also more tolerant of RF interference than HF and UHF, making them suitable for a variety of applications including access control, asset tracking, laundry, animal identification, automotive control and as vehicle immobilizers, and point-of-sale (such as Mobil/Exxon SpeedPass) applications.
Memory
LF RFID tags have a smaller memory capacity than UHF or HF, but they’re less susceptible to interference from liquids and metals. They’re best for applications like inventorying kegs of beer or automobiles, where the tag will be permanently attached to the item. LF tags can be encapsulated in glass or plastic to protect them from environmental damage.
UHF RFID tags have more memory than LF tags, but they also have lower read ranges and faster data transfer capabilities. This makes them better suited for applications such as tagging products, tracking inventory or identifying people and assets. They’re also more versatile than barcodes, allowing for a greater amount of information to be stored in a smaller space.
Every GS1-standard RFID tag has a unique TID or tag identity number. TIDs are encoded with a 16-bit Cyclic Redundancy Check (CRC-16) and a 16-bit Protocol Control (PC). This information is combined to create a 128-bit Electronic Product Code (EPC). The EPC encoder/decoder on this site allows you to translate between different forms of the EPC, including GS1-standard compressed and framed data.
Some LF RFID tags have additional writable memory called user memory. This memory is able to store a 32 bit (8 hex character) access password that’s used to unlock and write to the tag. Typically, this memory is perma-locked at the factory.
