Posted on 01 Sep, 2019
Radio Frequency Identification (RFID), also known as Radio Frequency Identification (RFID), is a communication technology that identifies specific targets and reads and writes related data through radio signals without the need to identify mechanical or optical contact between the system and a particular target.
Principles of RFID technology
The basic working principle of RFID technology is not complicated: after the tag enters the magnetic field, it receives the RF signal from the reader, and sends the product information (passive tag or passive tag) stored in the chip by the energy obtained by the induced current, or by The tag actively sends a signal of a certain frequency (Active Tag, active tag or active tag), and the reader reads the information and decodes it, and sends it to the central information system for data processing.
A complete RFID system consists of a reader and an electronic tag, the so-called transponder and application software system. The working principle is that the reader emits a specific frequency of radio wave energy to drive the circuit. The internal data is sent out, and the reader receives the interpretation data in order, and sends it to the application for corresponding processing. In terms of communication and energy sensing between the RFID card reader and the electronic tag, it can be roughly divided into two types: inductive coupling and backscatter coupling. Generally, the low-frequency RFID mostly adopts the first type, and the higher frequency mostly adopts the second method. The reader can be a read or read/write device depending on the structure and technology used, and is an RFID system information control and processing center. The reader usually consists of a coupling module, a transceiver module, a control module and an interface unit. The half-duplex communication is generally used for information exchange between the reader and the transponder, while the reader provides energy and timing by coupling to the passive transponder. In practical applications, management functions such as collection, processing, and remote transmission of object identification information can be further implemented through Ethernet or WLAN. The transponder is the information carrier of the RFID system, and the transponder is mostly composed of a coupling element (coil, microstrip antenna, etc.) and a microchip to form a passive unit.
The technology evolved from contactless radio frequency identification (RFID), developed by Philips Semiconductors (now NXP Semiconductors), Nokia and Sony, based on RFID and interconnect technology. Near Field Communication (Near Field Communication, NFC) is a short-range high-frequency radio technology that operates at a distance of 13 cm at a frequency of 13.56 MHz. Its transmission speed is 106Kbit / sec, 212 Kbit / sec or 424 Kbit / sec. At present, near field communication has passed the ISO/IEC IS 18092 international standard, the ECMA-340 standard and the ETSI TS 102 190 standard. NFC adopts both active and passive read modes.
Principle of NFC technology
NFC-enabled devices can exchange data in active or passive mode. In passive mode, devices that initiate NFC communication, also known as NFC-initiated devices (master devices), provide RF fields (RF fields) throughout the communication process. One of the transmission speeds of 106 kbps, 212 kbps or 424 kbps can be selected to send data to another device. The other device, called the NFC target device (slave device), does not have to generate a radio frequency field, but uses load modulation (load modulation) technology, which can transmit data back to the initiating device at the same speed. This communication mechanism is compatible with non-contact smart cards based on ISO14443A, MIFARE and FeliCa. Therefore, in passive mode, NFC-initiated devices can detect and establish contactless smart cards or NFC target devices with the same connection and initialization process. contact.
So NFC and RFID are different as follows
First, NFC integrates contactless readers, contactless cards and peer-to-peer functions into a single chip. RFID must be composed of readers and tags. RFID can only read and determine information, while NFC emphasizes It is the interactive version of information that says NFC is an evolved version of RFID. Both parties can exchange information in close proximity. The NFC mobile phone has a built-in NFC chip that forms part of the RFID module and can be used as an RFID passive tag for payment; The RFID reader is used for data exchange and collection, and can also perform data communication between NFC mobile phones.
Second, the NFC transmission range is smaller than that of RFID. The transmission range of RFID can reach several meters or even several tens of meters. However, because NFC adopts a unique signal attenuation technology, NFC has a close distance, high bandwidth and low energy consumption compared with RFID. Features.
Third, the application direction is different. NFC sees more about the communication of consumer electronic devices, and active RFID is better at long-distance identification. With the popularity of the Internet, mobile phones as the most direct intelligent terminal of the Internet will inevitably lead to a technological revolution. As with the previous Bluetooth, USB, GPS and other standard, NFC will become the most important standard for mobile phones in the future, through NFC. Technology, mobile payment, watching movies, and taking the subway can all be achieved, and will play a bigger role in our daily lives.