Radio Frequency Identification (RFID) is a non-contact technology which works on radio frequency to achieve auto-identification and data-gathering of a tagged object.

 

RFID transmissions mainly operate in three primary frequency ranges:

• LF ( Low-Frequency): 125 - 134 kHz
• HF ( High-Frequency): 13.56 MHz
• UHF ( Ultra High-Frequency): 433, and 860-960 MHz

 

 

In the Ultra High Frequency (UHF) band, where RFID tags work according to the principle of electromagnetic coupling, currently the most popular technology is based on ISO 18000-6C protocol,  common as EPC Class 1 Gen 2 (Gen 2 for short). The EPC 1 Class 1 Gen 2 standard was proposed by the private organization EPC global and adopted by the International Organization for Standards ISO 18000-6C in 2006.

 

The majority of UHF RFID systems use the 860 to 960 MHz frequency range and it is commonly known as 915 MHz Ultra High Frequency. However, the spectrum for North America is actually 902-928 MHz, while most of Europe is standardized on 865.5 to 867.5 MHz.

 

Compared with LF and HF RFID tags, UHF RFID tags have a much longer reading distance. There are two types of RFID in the Ultra High Frequency band - Passive RFID and Active RFID.

 

Passive UHF RFID

 

Passive UHF RFID tags are powered by UHF RFID reader that emits an electromagnetic field. Passive UHF tags can be detected from an average distance of about 5 - 6 meters, but larger UHF tags can achieve more than 25 meters under ideal conditions. Passive UHF is typically used in applications such as race timing, warehouse management, supply chain tracking, asset tracking, etc.

 

Active UHF RFID

 

Active UHF RFID tags are powered by an internal battery to continuously broadcast their own signals via BLE (Bluetooth Low Energy) or WiFi. There are three main frequencies used by active systems - 433 MHz, 915MHz and 2.45 GHz.

 

In the RFID system which uses an active beacon tag, the tag will send out its specific information every 3-5 seconds, and their signal is readable up to several hundreds meters away.

 

Active UHF RFID is very common in the oil and gas industry, vehicle tracking and electronic tolling.

Read more about Passive tag and Active tag

 

Read more about UHF 915MHz RFID Reader