Significado RFID

RFID , isso é identificação por radiofrequência, é um sistema sem fio que usa radiofrequência para realizar transmissão de dados bidirecional sem contato entre um leitor e um cartão de radiofrequência para obter a identificação do alvo e a troca de dados.

Definition
RFID (Identificação de rádio frequencia), aquilo é, identificação de rádio frequencia, é um sistema sem fio que usa radiofrequência para realizar transmissão de dados bidirecional sem contato entre um leitor e um cartão de radiofrequência para obter a identificação do alvo e a troca de dados. RFID 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.
RFID is divided into low frequency (LF), high frequency (HF), ultra-high frequency (UHF), and microwave (MW) according to different application frequencies. The corresponding representative frequencies are: low frequency below 135KHz, high frequency 13.56MHz, ultra-high frequency High frequency 860M~960MHz, microwave 2.4GHz.

Composition

• 1. Tags (ie radio frequency cards): RFID tags are commonly known as electronic tags, also known as transponders (Tag, Transponder, Responder). According to their working methods, they can be divided into two categories: active (active) and passive (passive). The source RFID tag has a short reading and writing distance, and the price is low; the active RFID tag can provide a longer reading and writing distance, but it needs battery power, and the cost is higher. Passive RFID tags are composed of tag chips and tag antennas or coils, and use the principle of inductive coupling or electromagnetic backscatter coupling to communicate with the reader. A unique code is stored in the RFID tag, usually 64bits, 96bits or even higher, and its address space is much higher than that provided by barcodes, so item-level item encoding can be achieved. When the RFID tag enters the active area of ​​the reader, an induced potential difference can be generated at both ends of the tag antenna according to the principle of inductive coupling (within the range of near-field action) or the principle of electromagnetic backscatter coupling (within the range of far-field action). A weak current is formed in the chip path. If the current intensity exceeds a threshold, the RFID tag chip circuit will be activated to read/write the memory in the tag chip. The microcontroller can further add passwords or anti-collision algorithms. and other complex functions. The internal structure of the RFID tag chip mainly includes four parts: radio frequency front end, analog front end, digital baseband processing unit and EEPROM storage unit.

• 2. Reader: Reader, also known as reader, interrogator (Reader, Interrogator), is a device that reads/writes RFID tags, mainly including radio frequency modules and digital signal processing units.

• 3.Antenna: The antenna is a device that realizes the spatial propagation of radio frequency signals and establishes a wireless communication connection between the RFID tag and the reader. There are two types of antennas in the RFID system, one is the antenna on the RFID tag, which has been integrated with the RFID tag, and the other is the reader antenna, which can be built into the reader or through a coaxial cable. Connect to the RF output port of the reader. Antenna products mostly use transceiver separation technology to realize the integration of transmitting and receiving functions. The importance of antennas in RFID systems is often overlooked. In practical applications, antenna design parameters are the main factors affecting the identification range of RFID systems. A high-performance antenna not only requires good impedance matching characteristics, but also needs to be specially designed for directional characteristics, polarization characteristics and frequency characteristics according to the characteristics of the application environment.

• 4. Middleware: Middleware is a message-oriented device that can accept requests from the application software side, initiate operations on one or more specified readers, receive and process the result data to the application software. Specialized software

• 5.Application software (Application Software): Application software is a human-computer interaction interface directly facing the end user of RFID application, assisting the user to complete the instruction operation of the reader and the logic setting of the middleware, and gradually convert the RFID atomic event into use. Business events that can be understood by readers and displayed using a visual interface. Since the application software needs to be specially formulated according to different enterprises in different application fields, it is difficult to have generality. From the perspective of application evaluation criteria, the user experience on the application software side is one of the decisive factors for judging the success of an RFID application case.

How it works

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 sends 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.