LF, HF, UHF What does it mean?
And we listen to the radio as simple as RFID tags and readers have to the same frequency modulation to work. LF, HF, UHF on frequency corresponding to different frequencies. Representative LF radio frequency in around 125KHz, HF radio frequency represents, so at 13.56MHz, UHF UHF radio frequency represents the range of 860 to 960MHz. For an RFID system, it is the concept of frequency reader through the antenna sending, receiving and reading the tag signal frequency range. From the application of concepts, the operating frequency of the RF tag is radio frequency identification system, directly determines the characteristics of various system applications. In the RFID system, the system worked like we usually listen to FM radio, like RFID tags and readers have the same frequency can be modulated to work.
RFID tags operating frequency determine not only the working principle of radio frequency identification system (inductive coupling or electromagnetic coupling), recognition distance, but also determines the RFID tags and readers to achieve the degree of difficulty and equipment costs. RFID applications or frequency band occupied by the internationally recognized, that are located in ISM band. Typical operating frequencies: 125kHz, 133kHz, 13.56MHz, 27.12MHz, 433MHz, 902MHz ~ 928MHz, 2.45GHz, 5.8GHz and so on.
According to different frequency, RFID tags can be divided into low-frequency (LF), High Frequency (HF), Ultra High Frequency (UHF) and microwave and other different types. Different frequency bands for RFID works differently, LF, and HF bands RFID tags generally using electromagnetic coupling principle, while RFID UHF and microwave bands generally using electromagnetic emission principle. Currently widely used in the frequency distribution in four kinds of bands, low frequency (125KHz), HF (13.54MHz), UHF (850MHz ~ 910MFz) and microwave (2.45GHz). Each frequency has its own characteristics, are used in different areas, so to proper use must first select the appropriate frequency.
Low frequency RFID tags, referred to as low-frequency tags, the operating frequency range of 30kHz ~ 300kHz. Typical operating frequency of 125KHz and 133KHz. Low-frequency tags are generally passive tags, and its working energy through inductive coupling from the reader's radiating near-field coupling coil obtained. Low-frequency tags and readers when transferring data between low-frequency tag reader antenna must be located near field zone. Low-frequency tag reading distance under normal circumstances is less than 1 meter. Typical applications for low-frequency tags: animal identification, container identification, tool identification, electronic locking anti-theft (with built-in transponder car keys) and so on.
High operating frequency band RF tag is generally 3MHz ~ 30MHz. Typical operating frequency of 13.56MHz. The band RFID tags, because it works exactly the same with the low-frequency tags that use inductive coupling work, so should be classified as low-frequency tags category. Other hand, according to the general division of radio frequencies, also known as high-frequency band of its work, it is also often be referred to as HF tags. Given the band RFID tags may be the most practical application of a large number of RFID tags, so we simply high and low understood as a relative concept, that will not cause confusion in understanding. For ease of description, we will call the IF frequency tag. IF label generally passive design master, whose work with the energy of low-frequency tags, also through inductive (magnetic) coupling coupling coil from the reader to get near-field radiation. Tag and reader for data exchange, the label must be in the reader antenna near-field region. IF tag reading distance under normal circumstances is less than 1 meter. IF label can easily be made because the card-shaped, widely used in electronic ticket, electronic / child / / certificates, electronic locking anti-theft (electronic remote lock controller), residential property management, building access control systems.
UHF and microwave frequency band referred to as microwave RFID tags RFID tags, the typical working frequency 433.92MHz, 862 (902) MHz ~ 928MHz, 2.45GHz, 5.8GHz. Microwave radio frequency tags can be divided into two types of active tags and passive tags. Work, the RF tag reader antenna radiation field in the far zone venue, tags and readers for the coupling between the electromagnetic coupling. Reader antenna radiation field of passive tags to provide RF energy, the active label wake. Corresponding radio frequency identification system reading distance is generally greater than 1m, typical of 4m ~ 6m, up to 10m or more. Reader antennas are normally directional antenna, the reader only within a directional beam antenna RF tag can be read / write. Since the increase in reading distance, the application may occur simultaneously in the reading area of ??a plurality of RFID tags, and thereby proposed a multi-tag read simultaneously needs. Currently, advanced radio frequency identification tag reader system are the multi-system is an important issue as a feature. UHF tag is mainly used for railway automatic vehicle identification, container identification, but also for road vehicle recognition and automatic toll collection systems.
The current level of technology, passive microwave RFID tags more successful products are relatively concentrated in the working frequency band 902MHz ~ 928MHz. 2.45GHz and 5.8GHz radio frequency identification system mostly semi-passive microwave RFID tags products available. Semi-passive tags commonly used button batteries, with a distant reading distance. The typical characteristics of microwave radio frequency tags focused on whether passive, wireless reading distance, whether to support multi-tag reading and writing, whether for high-speed recognition applications, the reader transmit power tolerance, RFID tags and reader prices, etc. . Can be written for the radio frequency tag, the distance is usually less than the reading distance is written, the write request because the greater energy. Microwave radio tag data storage capacity is generally limited to 2Kbits less, then a big storage capacity does not seem to make much sense, from a technical and application standpoint, microwave radio frequency tags are not suitable as a carrier of large amounts of data, and its main function is to identify items and complete non-contact recognition process. Typical data capacity indicators: 1Kbits, 128Bits, 64Bits and so on. Auto-IDCenter developed by the Electronic Product Code EPC capacity of 90Bits. Microwave radio tags Typical applications include mobile vehicle identification, electronic locking anti-theft (electronic remote lock controller), medical research and other industries.
Different frequencies have different characteristics labels, for example, low-frequency tags cheaper than the UHF tags, to save energy, through the scrap metal objects and strong, the operating frequency from radio frequency control constraints, the most suitable for a high water content of the object such as fruits, etc.; UHF effect a wide range of data transfer speed, but more energy, less penetrating, work area can not have too much interference, suitable for monitoring ports, warehousing and other logistics items; while high frequency identification tags are in short, read and write speed is centered, the product price is relatively cheap, such as an application on the electronic ticket card. Currently, different countries for the same band, the frequency of use are not the same. Europe is using UHF 868MHz, the United States is 915MHz. Japan currently does not allow to use ultra high frequency radio frequency technology. Currently in practice, the more commonly used is 13.56MHz, 860MHz ~ 960MHz, 2.45GHz other bands. Close RFID system mainly uses 125KHz, 13.56MHz, etc. LF and HF bands, the most mature technology; range RFID systems primarily use 433MHz, 860MHz ~ 960MHz UHF band, etc., as well as 2.45GHz, 5.8GHz and other microwave bands, there is more in the test which there is no large-scale applications.
China in the LF and HF bands RFID tag chip design technology is relatively mature, HF bands technical aspects of the design approach international advanced level, have been developed to meet ISO14443TypeA, TypeB and ISO15693 standard RFID chip, and successfully applied to the transportation card and second / Generation / certificates and other items.