The ultra-high frequency band within the RF spectrum ranges from around 300 MHz to 3 GHz; though, UHF RFID tag manufacturer offers between 860MHz and 960 MHz bands. The primary exceptions are modern RFID systems that operate about 433 MHz and 2.45 GHz.
UHF RFID tag systems function within these elected bands because of communication protocol standards put in place by GS1 and frequency regulatory standards set by individual countries or regions. These standards and regulations are one of the integral parts of RFID tags. If they didn’t exist:
Devices can interfere with each other and are either inoperable or have inferior efficacy as they compete for bandwidth. Extensive technology adoption is challenging because systems operate in distinct bands and have differing protocol or signaling standards.
UHF RFID tag systems do not communicate through magnetic coupling; instead, they use passive backscatter inflection according to GS1 EPC global UHF Class 1 Gen 2 specifications.
UHF RDIF waves are, on average, about 33 centimeters in length; but, in the higher tag frequencies, such as 2.45 GHz, they are as small as 12 centimeters in length. The UHF RFID tag has typically deployed in one of two types of RFID tag systems – passive or active. Let’s read about passive UHF RFID:
Passive UHF RFID
The describing quality of passive UHF RFID systems is how the RFID tags purpose. Passive UHF tags rely on passive backscatter variation to function and have no additional power source. In short, it means that the RFID reader sends the energy through the antenna as RF tag waves to the UHF RFID tags for them to become invigorated and respond to the reader. The response is so-called backscatter as the tag scatters around a portion of the energy that it gets from the reader. As there is no added power available to the tag other than what is providing by the reader, these systems have a maximum tag read range of around 30 meters.
UHF passive tags have some of the lowest costs because of widespread adoption. Volume quantities of UHF RFID can dip as low as $0.10 a tag though maintaining an average read range of 2 to 5 meters. UHF passive tags have decreased in cost substantially over the years, letting companies and individuals use low-cost label tags as throwaway asset identifiers.
Passive UHF tags are sensitive to both liquids and metal. It is because the UHF waves reflect off, bend within, or absorb into non-RF-friendly materials. However, performance degradation in the presence of liquids and metals is difficult to overcome; the UHF RFID tag manufacturer mitigates interference by analyzing the application environment and retaining techniques to overcome obstacles, like installing RF shielding and using metal-mount RFID tags.
Passive UHF tags come in several form factors and are generally subdivided into rugged, label tags, high-temperature, high memory, etc. The RFID tags tend to last the application’s lifetime unless hurt by wear and tear, and because they never have batteries, their lifespan is not reliant on a power source.
The hardware for the UHF RFID tag system requires a more significant investment than HF and LF RFID system equipment. Readers range between $400 for a low-cost reader up to around $2,500 for a rugged handheld RFID tag reader.