LF HF and UHF RFID Tag
Both LF and HF frequencies are on the lower end of the RFID electromagnetic spectrum, which indicates RFID tags in these frequencies will have relatively short read ranges but a greater ability to be received or transmitted in all directions.
They also have better operational success in moist conditions, albeit slower transmissions under all conditions. Both have the ability to work in environments involving metal, often with tag modification.
This being said, low-frequency RFID transmission can activate tags behind thin metal substances whereas high-frequency RFID works with tags on metal surfaces - the preposition makes a subtle, but significant, difference.
For example, in a grocer’s meat case, an LF reader can read a ham’s LF RFID tag behind aluminum foil; an HF reader would need the HF RFID tag on the outside of the foil to be read.
Both frequencies, LF and HF, can be used in moist situations where higher frequencies such as UHF stumble for reads. Nevertheless, LF has the advantage over HF when working with moisture.
Take, for instance, an LF RFID chipped cat (mostly made up of water) would use a feeder equipped with an LF RFID reader to access food. Although the cat would probably obtain access control to nourishment under either frequency, the LF feeder would be slightly more dependable and LF tags would be less expensive than HF.
The cat’s LF RFID device, of course, would be close to the reader because LF read range is limited to centimeters or inches.
Most commonly, low frequency tags are used for access control and animal identification.
Likewise, if RFID enabled, the tiny labels on fruit would show benefit from low frequency tagging read by handheld readers that come close to the produce.
In this case, produce management accurately measures quality and quantity for better economic control, but might entail more manual labor.
However, where proximity-to-read is more than a pinky finger away, HF (high-frequency) tags and readers with a transmission/read range up to a yard might be the better choice for produce handlers even if slightly less accurate.
Reads could be made approximately a yard away leading, perhaps, to installation of a shelf RFID management system.
