What Are The Operating Frequencies Of The RFID System?

For an RFID system, its frequency band concept refers to the frequency range of the tag signal that the reader sends, receives and reads through the antenna. From the application concept, the working frequency of the radio frequency tag is the working frequency of the rfid system, which directly determines the characteristics of various aspects of the system application. In the RFID system, the system works like we usually listen to FM radio, and the radio frequency tag and the reader must be modulated to the same frequency to work.
The working frequency of the radio frequency tag not only determines the working principle of the radio frequency identification system (inductive coupling or electromagnetic coupling) and the identification distance, but also determines the difficulty and equipment cost of the radio frequency tag and the reader. The frequency bands or frequency points occupied by RFID applications are recognized internationally, that is, in the ISM band. Typical operating frequencies are: 125kHz, 133kHz, 13.56MHz, 27.12MHz, 433MHz, 902MHz~928MHz, 2.45GHz, 5.8GHz, etc.
According to different operating frequencies, RFID tags can be divided into different types such as low frequency (LF), high frequency (HF), ultra high frequency (UHF) and microwave. The working principles of RFID in different frequency bands are different. The LF and HF frequency band RFID tags generally use the principle of electromagnetic coupling, while the RFID in the UHF and microwave frequency bands generally use the electromagnetic emission principle. At present, the frequencies widely used in the world are distributed in four frequency bands, low frequency (125KHz), high frequency (13.54MHz), ultra-high frequency (860MHz～960MHz) and microwave (2.45GHz). Each frequency has its own characteristics and is used in different fields, so to use it correctly, you must first select the appropriate frequency.
Low-frequency radio frequency tags, referred to as low-frequency tags for short, have an operating frequency range of 30kHz to 300kHz. Typical operating frequencies are 125KHz and 133KHz. Low-frequency tags are generally passive tags, and their working energy is obtained from the radiated near field of the coupling coil of the reader through inductive coupling. When transmitting data between a low-frequency tag and a reader, the low-frequency tag needs to be located in the near-field area radiated by the antenna of the reader. The reading distance of low-frequency tags is generally less than 1 meter. Typical applications of low frequency tags are: animal identification, container identification, tool identification, electronic lock theft prevention (car keys with built-in transponders), etc.
The working frequency of the middle and high frequency band radio frequency tags is generally 3MHz ~ 30MHz. The typical operating frequency is 13.56MHz. The radio frequency tag in this frequency band, because its working principle is exactly the same as that of the low frequency tag, that is, it works in the way of inductive coupling, so it should be classified into the low frequency tag category. On the other hand, according to the general division of radio frequency, its working frequency band is also called high frequency, so it is often called high frequency tag. In view of the fact that the radio frequency tags in this frequency band may be the largest number of radio frequency tags in practical applications, as long as we understand high and low as a relative concept, it will not cause confusion in understanding. For ease of description, we call it an IF RFID tag. Intermediate frequency tags generally also use passive devices, and their working energy, like low-frequency tags, is also obtained from the radiated near field of the reader coupling coil through inductive (magnetic) coupling. When the tag exchanges data with the reader, the tag must be located in the near-field area radiated by the reader antenna. The reading distance of IF tags is generally less than 1 meter. Because the IF tag can be easily made into a card shape, it is widely used in electronic ticket, electronic ID card, electronic lock and anti-theft (electronic remote control door lock controller), residential property management, building security system, etc.