LF RFID Tag
LF RFID tags can be used for a variety of applications including inventory, employee tracking, and customer identification. They have a shorter read range than higher frequency technologies, but perform well in environments that are more challenging for other types of RFID systems.
Various time-domain encoding methods exist for this frequency, including pulse width modulation and group delay coding. Group delay coding uses dispersive transmission line C-sections to produce different group delays for each of the frequency-related reflected pulses.
LF Antennas
The signal that reaches the tags from the reader induces in them a minimum electric current that operates their integrated circuit and generates and transmits a response. This signal is transmitted by LF antennas (S114).
The LF band covers frequencies between 30 KHz and 300 KHz, but LF RFID systems usually operate right around 125 KHz. This frequency provides a short reading range, but it is resistant to interference. LF transmissions can also penetrate metal surfaces and items containing liquid, and they are often used in moisture-prone environments. LF RFID systems can be used for access control and livestock tracking, among other things.
LF antennas are typically designed to RFID Reader be vertically polarized, since the electromagnetic waves travel in the ground wave mode that follows the contour of the Earth. LF readers are connected to the LF antennas via a twisted pair cable or connector. These LF antennas are available in different versions to meet various requirements for maximum performance.
Industrial-grade LF readers and antennas have robust housings with protection level IP67 and are easy to integrate into your system. These LF readers and antennas have a read/write head that can be mounted either in or on the tag, and they provide varying degrees of reading range depending on the combination of reader/antenna and operating mode, mounting material, and clear zone from metal.
LF Tags
LF tags operate in the 125 kHz frequency band and provide a shorter read range than UHF or HF tags. They’re less susceptible to interference from metals or liquids and can be used in humid conditions or for applications where the RFID tag needs to be hidden. LF tags are ideal for inventorying library media, for tracking beer kegs, and for granting access control to people and vehicles at theme parks.
Unlike Named Resource policies, where you specify a single database or table for permissions, LF-Tag permissions are based on an LF-Tag expression that matches to the corresponding LF-Tag values in the table. This is a more scalable approach as you can grant permissions to multiple resources at once using the same LF-Tag expression, which is updated whenever a tag on one of these resources changes.
Clear laminate LF RFID tags are popular for tote or pallet identification and available with or without sticky backing. Plastic wedge or coffin LF tags are suitable for space-restricted applications and offer the durability to survive duress. Glass ampoule and ear tags are injectionable for animal ID or security applications. The RFID nail tag is commonly used for tagging tress or wood assets in construction and transportation projects, and has the added benefit of being rust resistant in wet environments.
LF Readers
LF RFID readers interrogate tags at close proximity with a read range of about 10 cm (1 foot). LF is less sensitive RFID Reader to interference from metals, liquids and other radio waves. This makes it an excellent choice for use in applications such as security patrol, mining and railway systems where the reader is often mounted on or in railcars.
Alternatively, you can opt for HF readers that operate in the 3 MHz to 30 MHz band and provide a general read range of about 1 m. HF is also a popular option for payment card and proximity card technology. HF RFID readers usually have Wi-Fi options for applications in environments with an active network connection. They may also have Bluetooth options for handheld cradles and mounts to connect to smart devices.
RF tags can store and buffer tag read data on the device and automatically upload it to a server when the application needs it. This decentralizes information, which reduces the load on higher system software and speeds up deployment. By storing work instructions in the tag, it can allow work to continue offline when a computer or network is unavailable, which helps eliminate errors and decrease production stoppages. It can also record inspection results with a time stamp in order to support continuous improvement. This is why RF tag technology is used in manufacturing, inspection and maintenance environments.
LF Transmitters
LF transmitters emit electromagnetic waves in the frequency range between 30 kHz and 300 kHz. The transmitters are used for communication between mobile devices and the Internet of Things (IoT). Unlike higher-frequency tags, LF transponders use crystal-less electronics to minimize size and weight. They are also more durable than previous models, able to withstand up to 50,000 g’s of vibration and impact.
During a 15-day period from 23 February 2016 to 1 March 2016, the VLF transmitter emissions of LF transponders were detected by the HFR instrument onboard the Van Allen Probes A and B. The LF signal was observed at an intensity level below 5 pT over two different L-shell regions. This is a very low-intensity phenomenon, probably related to the geomagnetic activity.
LF RFID tags are passive and don’t require batteries, but are vulnerable to environmental factors such as liquids or metals. These tags are a great option for tracking assets that must be kept in an enclosed space, such as warehouse items. They are also a good choice for applications that require a small foot print and excel in environments with high temperatures. LF RFID tags can also work well in moist conditions where higher-frequency tags like UHF struggle for reads. The LF tag is often used as an embedded component of a product, such as in the case of a ham’s RFID tag being placed behind aluminum foil in a grocery store meat case.
