Introduction to Low Frequency, High Frequency, and Ultra High Frequency RFID Tags

According to the frequency, RFID tags can be divided into low-frequency tags (LF), high-frequency tags (HF), and ultra-high frequency tags (UHF).  

The main frequency of low-frequency RFID tags is 125kHz or 134kHz, and they work using magnetic induction coupling, with the coupling element being an induction coil. The reading distance varies from a few centimeters to several tens of centimeters depending on the antenna size and power of the reader/writer. Due to the low operating frequency, the communication rate between tags and readers is also relatively low. Mainly used for vehicle management, animal tracking, etc.

The main frequency of high-frequency RFID tags is 13.56MHz, and they also work using magnetic induction coupling, with the coupling element being a coil. Compared with low-frequency RFID tags, the data transmission rate is higher. Its reading distance is generally less than 10cm. Therefore, high-frequency RFID tags have been widely used in fields such as electronic payment, access control, and electronic tickets.

The main frequency of ultra-high frequency RFID tags is 915MHz, with additional frequencies of 433MHz and 2.4GHz. The working mode used is electromagnetic wave propagation coupling. The reader antenna provides radio frequency energy to the tag, and the tag antenna receives the radio frequency energy and sends the electronic encoded information of the tag to the reader through backscatter modulation. The tag works in the far field of the reader/writer antenna. The reading distance is generally greater than lm, with a typical value of 3-8m and less than 20m. The data communication rate is relatively high, up to 640kbit/s, and can read thousands of tags at once. The reader antenna is generally a directional antenna, and only tags within the beam range of the reader antenna can be read. With the development of technology and continuous cost reduction, the application of ultra-high frequency RFID technology is becoming increasingly widespread. It has enormous potential in fields such as traffic management, logistics management, asset management, and warehouse management.