General RFID FAQs
UHF RFID FAQs
RFID stands for Radio-Frequency Identification. It is an identification technology (of a person, an animal, or an object) based on radio-frequency communication. The identification takes place via RFID Tag, or transponders equipped with a unique identification number and, depending on the models, also with additional memory. RFID tags, particularly passive ones, have a particularly low cost (about 0.05) and do not require power. For this reason, they can be applied to individuals and things in different fields: logistics, inventory, supply chain, automation, marketing, and many others, including several applications in the Internet of Things.
An RFID Tag is a chip, or transponder, with an antenna that amplifies the radio signal. In the most common form, an RFID Tag looks like a label with the circuit visible in transparency. It is also called wet inlay, when it is adhesive, or dry inlay when it is not.
Active tags have an internal battery, which is generally used to increase the transmission power and, consequently, the reading distance. A typical example of passive tags is the Bluetooth Beacon.
The passive tags, on the other hand, do not have an internal power supply: a capacitor is used which, once charged, generates the electromagnetic field that carries the information contained in the chip. The solicitation takes place through an RFID reader, which usually takes a fraction of a second to feed the Tag and read it. The most common tags are the passive ones, because of the great advantage of not needing a battery.
For completeness, there are also semi-active tags, therefore equipped with power supply. This power supply is not used for radio circuits, but is used for additional functions, such as temperature or movement sensors.
On RFID.it, we mainly deal with passive Tags.
The RFID tags are read / detected by special fixed or mobile devices, called RFID readers, or RFID readers. These readers solicit the transponder by induction or electromagnetism, which activates and transmits the information it contains. RFID readers can have an integrated or external antenna. If the model supports it, more than one antenna can be connected to a reader, so as to identify tags in different points, or to cover a certain gap accurately.
Depending on the frequency of the chip, there are several RFID categories, with their own characteristics. Below, we report the most common, governed by ISO standards.
On RFID.it, we deal with RFID LF, HF and UHF technology.
It is the second generation EPC (Electronic Product Code) protocol, designed to operate internationally. The EPC Gen is the center of attention because a convergence between the UHF Gen 2 standards and a revision of the ISO -6 seems likely, ie it applies only to UHF tags. The unification process could contribute to further acceleration in the global adoption of RFID.
The GS1 EPC Gen2 air interface protocol, first published by EPCglobal in , defines the physical and logical requirements for an RFID system with passive tags, operating in the UHF frequency range from 860 MHz to 960 MHz. In the last ten years, EPC Gen2 has established itself as a standard for UHF implementations in multiple industries and is at the center of increasingly RFID implementations.
In , Gen2X has been released, with many significant improvements in terms of performance, security and functionality. Learn more.
RAIN RFID is a global alliance that promotes the universal adoption of RFID UHF technology in a similar way to other wireless technology organizations including NFC Forum, WiFi Alliance and Bluetooth SIG. RAIN uses the GS1 UHF Gen2 protocol which ISO/IEC has standardized as -63. The word RAIN - an acronym derived from RAdio Frequency IdentificatioN - is intended as a nod to the connection between UHF RFID and the cloud, where RFID-based data can be stored, managed and shared via the Internet. A RAIN RFID solution uses a reader to read and write a tagged item, manage data and act.
Historically, 2 slightly different operating standards have spread: one for the typically European market, operating at a frequency of around 860 MHz, and one for the American market, which operates at around 960 MHz. The ISO -63 standard distinguishes passive UHF Tags operating at both frequencies, so they can be used globally without problems.
The UHF RFID tags published on RFID.it are all compliant with the RAIN standard and ISO -63.
UHF technology allows to identify a very large number of transponders (over 700 units), using anti-collision systems (see below). The maximum number depends on the transit speed, the type of information to be collected for each transponder and the type of RFID controller that is used (memory buffer available).
UHF chips can be classified in different ways, but mainly based on the size and characteristics of the EPC, TID and user memory. For more information on the technical characteristics of the chips, click here.
The memory capacity (user memory) of a UHF chip is currently 512 bits (64 bytes) or bits (128 bytes). Chips with a capacity of 8 kbytes have recently been announced, but the costs are still very high.
The communication distance of UHF technology is one of the strengths of this particular frequency, as it allows a greater range than other technologies. The distance varies according to the readers and tags used. The mobile PDAs equipped with RFID UHF technology allow to communicate with the tags at distances of 4-6 meters, while the Long Range UHF type controllers detect the tags at 10/15 meters. With specific on-metal passive tags, communication distances of up to 30/35 meters are possible.
For the most common tags, such as wet inlays (plastic labels with embedde chip and antenna), the operating temperature is between -20°C and +70°C. For extreme temperatures, special tags are made, with more insulating casings, suitable to resist in more hostile contexts.
Metal, carbon and all non-"radiolucent" conductive materials can create the Faraday Cage effect.
In particular, UHF frequencies are attenuated above all by liquids. However, there are transponders that can be applied to liquids with suitable insulating materials.
For metallic materials, on the other hand, special Tags have been designed, called shielded, or anti-metal, or even on-metal, which guarantee an optimal reading even when applied to metal surfaces.
A "linear polarization" antenna is a device that focuses the radio energy coming from the reader in a single orientation (or polarity). This allows to increase the reading distance, succeeding in increasing the penetration capacity of the emitted radio wave; "Circular-polarized" antennas instead emit radio waves in a circular way (as you can guess from the name): in this case the reader radius of action is smaller but there are more possibilities to "hit" the Tag; in fact this latter type of antenna is used in situations in which the tags applied to the products cannot be controlled, whereas instead in the case of readers equipped with a "linear-polarized" antenna, the labels must be aligned very precisely in the direction of the antenna itself.
Anti-collision systems are procedures that are used to manage the reading of several tags simultaneously; technically these systems prevent the annoying episode of the overlapping radio waves, emitted by different tags, which end up disturbing each other. Within a single electromagnetic field generated by a single antenna of a reader, it is possible to manage the reading of different Tags thanks to algorithms called precisely anti-collision, which regulate the time intervals in which the Tags must be read: in this way no interference occurs and there is no risk of receiving incorrect or inaccurate information.
The interfaces available on the host side are the most common and include: Ethernet RJ45, USB, RS232, RS485, TTL, Wi-Fi, GPRS, TTL / RS232. Various models of controllers are also available with Inputs, Outputs and relays, integrated microcontrollers for the development of embedded applications.
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RFID devices emit radio waves, very low frequency electromagnetic waves, harmless to our body.
However, we live in a world pervaded by decades of electromagnetic waves, not least those of 5G, but consider that even a normal television or an old radio emit electromagnetic waves. It is therefore more than half a century that our bodies coexist with electromagnetic waves of any kind without ever having been certified for health damage.
October 01 ,
How to choose a uhf rfid card reader? How does it work?
RFID is the English abbreviation of Radio Frequency Identification. In layman's terms, an RFID reader is an automatic identification device that can read electronic tag data. According to the frequency of reading tags, it is divided into low frequency, high frequency and ultra-high frequency card readers. The rfid card uhf needs to be equipped with an RFID antenna to read the tag information.
Introduce
RFID is the English abbreviation of Radio Frequency Identification. In layman's terms, an RFID reader is an automatic identification device that can read electronic tag data. RFID radio frequency identification is a non-contact automatic identification technology. It automatically identifies target objects and obtains relevant data through radio frequency signals. The identification work does not require manual intervention and can work in various harsh environments. RFID technology can identify high-speed moving objects and identify multiple tags at the same time, which is fast and convenient to operate.
"First, it can identify a single very specific object, instead of only identifying one type of object like a barcode; second, 10dbi uhf rfid antenna,it uses radio frequency, which can Data is read through external materials, while barcodes must rely on lasers to read information; third, multiple objects can be read at the same time, while barcodes can only be read one by one. In addition, the amount of stored information is also very large"
Soft ferrite
When the antenna of the non-contact IC card reader/writer is in an environment with a lot of metal substances, installing a plate made of ferrite material on the back of the antenna can reduce the impact of metal substances on the card reading performance and stability. Soft ferrite is easy to cut, but its performance is not as good as that of hard ferrite. The thickness is 1.7mm, the size can be cut arbitrarily, and the frequency range is wide.
Hard ferrite
When the antenna of the non-contact IC card reader/writer is in an environment with a lot of metal substances, installing a plate made of ferrite material on the back of the antenna can reduce the impact of metal substances on the card reading performance and stability. Hard ferrite is cumbersome to manufacture, requires mold opening and machining, but has good performance, is hard, cannot be cut, needs to be customized in size, and has better properties than soft ferrite.
Principle
The basic working principle of rfid tag passive uhf ,RFID technology is not complicated: after the tag enters the magnetic field, it receives the radio frequency signal sent by the reader, and transmits the product information (Passive Tag, passive tag or passive tag) stored in the chip with the energy obtained by the induced current. , or actively send a signal of a certain frequency (Active Tag, active tag or active tag); after the reader reads and decodes the information, it is sent to the central information system for related data processing.
The rapid rise of radio frequency identification technology (RFID) is not only the result of technological development, but also the embodiment of application requirements. Since the s, various applications around RFID have sprung up like mushrooms after a rain. Today, we will briefly introduce RFID technology and its most important product - uhf rfid reader.
Division of frequency bands
In the field of radio frequency, electromagnetic waves are divided into 6 parts by frequency. The main frequency bands of RFID: low frequency, high frequency, ultra-high frequency and microwave.
Low frequency (30300kHz)
Common operating frequencies are low-frequency 125kHz and 134.2kHz. Low-frequency RFID is mainly used in short-distance, low-cost applications, such as access control, campus cards, gas meters, water meters, etc.
High frequency (330MHz)
The high-frequency HF RFID equipment works in the 13.56MHz frequency band. The system transmits energy through the inductive coupling of the antenna coil, and the magnetic field energy decreases rapidly through inductive coupling. The magnetic field signal has distinct read area boundaries. It is mainly used to identify people or items within 1 meter. It mainly follows two protocols: ISO/IEC (A, B) protocol, ISO/IEC protocol.
ultra-high frequency(825MHz--905MHz) for UHF car access control system
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