RFID tags can be divided into low frequency (LF), high frequency (HF), and ultra high frequency (UHF)

For an RFID system, the concept of Frequency Band refers Frequency Range of tag signals sent, received, and read by the reader through an antenna . In terms of application concept, the operating frequency of the RF tag, that is, the operating frequency of the RFID system, directly determines all aspects of the system application. In an RFID system, the system works just like we usually listen to FM broadcasts. RF tags and Readers must be modulated to the same frequency before they can work.
RF tag The working frequency not only determines the working principle (inductance coupling or electromagnetic coupling) of the RFID system, but also determines the difficulty of radio frequency tags and reader implementation and equipment costs. . The frequency bands or frequency points occupied by RFID applications are internationally recognized. ISM band . Typical Operating frequencies include: 125 Khz, 133 kHz, 13.56 MHz, 27.12 MHz, 433 MHz, and 902mhz ~ 928 MHz, 2.45 GHz, and GHz.
According to the operating frequency, RFID tags can be divided into low frequency (LF), high frequency (HF), ultra high frequency (UHF) and microwave. RFID in different frequencies works in different ways. RFID tags in LF and HF frequencies generally use electromagnetic coupling, while RFID in UHF and microwave frequencies generally uses electromagnetic emission. At present, the frequency widely used in the world is distributed in four kinds of bands: low frequency (125 Khz), high frequency (13.54 MHz), and ultra high frequency (850mhz ~ 910mfz) and microwave (2.45 GHz ). Each frequency has its own characteristics and is used in different fields. Therefore, to use it correctly, you must first select the appropriate frequency.
Low-Frequency Band RF tags, referred to as low-frequency tags. Their operating frequency ranges from 30 kHz ~ 300 kHz. Typical Operating frequencies include 133 kHz and kHz. Low-frequency tags are generally passive tags, and their working energy passes throughInductance CouplingMethod obtained from the radiation near field of the reader coupling coil . When transmitting data between a low-frequency tag and a reader, the low-frequency tag must be located in the proximity zone of the reader antenna radiation. The reading distance of low frequency labels is generally less than 1 meter. Typical applications of low-frequency tags include animal recognition, container recognition, tool recognition, and electronic locking and anti-theft (car keys with built-in Referer.
The operating frequency of high-frequency RF tags is generally 3 MHz ~ 30 MHz. Typical operating frequency is 13.56 MHz. The RF tags of this band work in the same way as those of the low-frequency tags, that is, the RF tags work in Inductor coupling mode. Therefore, they should be classified as low-frequency tags. On the other hand, according to the general division of radio frequency, its working frequency band is also called high frequency, so it is also often referred to as high frequency tags. Given that the RF tags of this frequency band may be the most widely used RF tags in practical applications, as long as we understand high and low as a relative concept, it will not cause confusion in understanding. To facilitate the description, we call it an intermediate frequency RF tag. In general, if tags use a passive active device, and their working energy is the same as that of low-frequency tags. The inductance (magnetic) coupling method is obtained from the radiation near field of the reader coupling coil. . When a tag is used to exchange data with a reader, the tag must be located in the near Zone of the reader antenna radiation. The read distance of the IF tag is generally less than 1 meter. If tags can be easily made into cards, they are widely used in electronic tickets, electronic ID cards, electronic locks and theft (Electronic remote control lock controller), residential property management, building access control systems, etc.
The RF tags for ultra-high frequency and microwave frequencies are short for microwave RF tags. Their typical operating frequencies include 433.92 MHz and 862 (902) MHz ~ 928 MHz, 2.45 GHz, and 5.8 GHz. Microwave RF tags can be classified into active tags and passive tags. During operation, the RF tag is located in the far area of the antenna radiation field of the reader. The coupling mode between the tag and the reader is electromagnetic coupling. The reader antenna radiation field provides RF energy for passive tags to wake up the active tags. The reading distance of the RFID system is generally greater than 1 m, typically 4 m ~ 6 m, up to 10 m. Reader antennas are generally oriented antennas, and only RF tags within the reader antenna's targeted beam range can be read/written. Due to the increase of reading distance, multiple RF tags may appear in the reading area at the same time, thus the demand for simultaneous reading of multiple tags is raised. Currently, the advanced radio frequency identification system regards the multi-tag reading problem as an important feature of the system. UHF tags are mainly used for automatic identification of railway vehicles and container identification. They can also be used in Highway Vehicle Identification and automatic charging systems.
At the current technical level, the products with relatively successful passive microwave RF tags are relatively concentrated in the 902mhz ~ MHz operating frequency. The 2.45ghz and 5.8ghz radio frequency identification systems are mostly semi-passive microwave radio frequency tags. Semi-passive labels are generally powered by button batteries, with a long reading distance. The typical features of microwave RF tags are passive or wireless read/write distance, whether multi-tag read/write is supported, whether it is suitable for high-speed recognition applications, and the reader's transmit power margin, RF tags and reader prices. For RF tags that can be written wirelessly, the write distance is usually less than the read distance, because the write requires more energy. The data storage capacity of microwave RF tags is generally limited to 2 kbits, and the larger storage capacity does not seem to be of great significance. From the technical and application perspective, microwave RF tags are not suitable for serving as a carrier for a large amount of data. Their main function is to identify items and complete the non-contact identification process. Typical data capacity indicators include 1 kbits, 128 bits, and 64bits. Product electronics developed by Auto-ID Center Code The EPC capacity is 90 bits. Typical applications of microwave RF tags include mobile vehicle identification, electronic locking anti-theft (Electronic remote control lock controller), medical research and other industries.
Tags of different frequencies have different characteristics. For example, low-frequency tags are cheaper than ultra-high frequency tags, saving energy and penetrating waste metal objects. The operating frequency is not subject to radio frequency control, it is most suitable for objects with high water content, such as fruits. The ultra-high frequency function has a wide range, and the data transmission speed is fast. However, it consumes a lot of energy and has a weak penetration ability. The operation area cannot have too much interference, it is suitable for the monitoring of goods in the logistics field such as the port and warehouse. The high-frequency label is short-range identification, reading and writing speed is also centered, and the product price is relatively low, such as the application on the electronic ticket card.
Currently, different countries use different frequencies for the same band. In Europe, the ultra-high frequency is 868 MHz, while in the United States, the ultra-high frequency is 915 MHz. At present, Japan does not allow the use of uhf rf technology.
Currently, 13.56 MHz and MHz ~ are commonly used in practical applications ~ 960 MHz and GHz. Close-range RFID systems mainly use 125 Khz, 13.56mhz, and other LF and HF frequencies, with the most mature technology. Long-range RFID systems mainly use 433 MHz, 860mhz ~ 2.45 MHz and other ultra-high frequency bands, as well as GHz and GHz microwave frequencies, are still under test and have no large-scale application.
China's LF and HF Band RFID tag chip design technology is relatively mature, the design technology of HF Band is close to the international advanced level, we have independently developed RFID chips that comply with the type A, type B, and iso15693 standards and have successfully applied them to projects such as traffic card and the Second Generation ID card.