RFID (radio frequency identification) radio frequency identification technology, also known as "electronic tag", is a non-contact automatic identification technology rising in the 1990s. When no one intervenes, it can automatically identify the target object and obtain relevant data through radio frequency signals. RFID technology has a flexible working environment. In addition to working in extreme environments, it can also identify high-speed moving objects and multiple tags at the same time.

       RFID is mainly composed of tag, reader / reader and antenna.

       labelIts main function is to attach to the object to identify the target object. It is composed of coupling elements and chips with unique electronic code;

       Reader / reader writerThe main function of is to read (or write) label information, which is divided into handheld and fixed;

       antennaIts function is to transmit RF signals between the tag and the reader.

       The basic work flow of RFID is that the reader sends a certain frequency RF signal through the transmitting antenna, the tag generates induced current after entering the electromagnetic field, the tag obtains energy, is activated, sends the product information stored in the chip, the receiving antenna receives the carrier signal sent from the tag, and transmits it back to the reader through the antenna regulator, The reader demodulates and decodes the signal and sends it to the background main system for processing. This kind of tag is called passive tag or passive tag. The active tag or active tag actively sends a signal of a certain frequency. After the reader reads and decodes the signal, it is sent to the main system for relevant data processing. The active tag is equipped with battery power supply, which has higher cost, longer reading and writing distance and larger volume compared with the passive tag.

▲ working principle of RFID identification technology

       The basic working principle of RFID technology is not complex: after the tag enters the magnetic field, it receives the RF signal sent by the interpreter, sends 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 the signal of a certain frequency (active tag, active tag or active tag); The interpreter reads and decodes the information and sends it to the central information system for relevant data processing.

▲ RFID system architecture diagram

       RFID can be classified in many ways, including classification by working frequency, classification by power supply mode, classification by application scope and classification by data reading and writing type. See the figure below for details:

       The working frequency of RFID application system is wide, ranging from 100kHz to 5GHz. At present, the main international frequency bands are:Low frequency (125khz-134khz), high frequency (13.56MHz), UHF (860m-960mhz), and microwave (2.45GHz, 5.8GHz) products。 For the antenna, when the transmitted signal wave exceeds the effective size of the antenna for a long time, the antenna is obviously inductive as a circuit load, resulting in the signal energy being stored in the near-field region of the antenna, so it can not be propagated efficiently. The antenna is limited by the application environment and weight, and often can not be large enough. Taking the frequency of 13.56MHz as an example, the corresponding one eighth wavelength is about 2.7m. Therefore, UHF frequency band has become the first choice for the application of passive RFID in long-distance (0.5m ~ 10m) transmission. Compared with the 2.4GHz band, the effective size of the 900MHz band antenna is larger, which means that more energy can be received.

▲ schematic diagram of RFID frequency band distribution

▲ UHF (ultra high frequency) RFID band allocation in major countries and regions

▲ protocol standards and features related to RFID Technology

       With the more and more extensive application of RFID in UHF, the corresponding technology and product standardization work is also ongoing. The current industry specification ISO / IEC 18000-63 clearly stipulates the technical level of RFID. Passive RFID communication adopts half duplex mode. The RFID reader and writer first uses pie coding to send UHF energy signal with broadcast nature. The signal has been digitally modulated by ask or PSK before coding. The tag receives the RF signal transmitted by the reader and demodulates it, and returns the data to the reader and writer through backscatter technology. For UHF electronic tag, the characteristics of tag chip are very important. It directly determines the storage capacity, read-write limit distance, read-write speed, read-write parameters, information security and other vital parameters of tag products. It is the core technology of electronic tag products. Figure 5.1 is the schematic diagram of UHF electronic tag chip architecture.

▲UHF electronic label chip architecture

       A set of RFID scheme needs design, reader, antenna, tag, bracket or cabinet, application software, software integration services, etc.Its industrial chain is divided very finely, and there are many manufacturers in each link.Here are some representative manufacturers for reference。

       Chip:

       RFID chip is divided into tag chip and reader chip. The development trend of its technology will still be lower power consumption, longer distance, faster reading and writing speed, higher reliability and security, and lower cost. For domestic RFID chip manufacturers, the most important thing is stability, including the production process needs to be improved.

       1. NXP

       NXP's RFID chips include UHF, HF, NFC and LF. The products have been widely used in warehousing, clothing retail, automotive electronics, brand protection tracking and livestock tracking.

       For example, ucode 8 rain RFID, launched in 2017, is more sensitive and easier to embed into tags, which is usually used in UHF RFID tags. The chip can also add a special ID number to the company using the label to realize brand identification.

       2. Alien technology

       American Yilian technology is a leading supplier in the industry, specializing in providing UHF Passive RFID chips in line with EPCglobal Gen2 and ISO / IEC 18000-6c standards, as well as technologies and products related to tags, readers and professional services.

Higgs-4 is a highly integrated single-chip EPC Gen2 UHF RFID tag chip. It can write data at low RF power, and can also write data to tags at the same time in retail applications with a large number of tags.

       3. Impinj

       Yingpinjie is the world's leading supplier of UHF Gen 2 RFID solutions. Its products include high-performance tag chip, reader, reader chip, software, antenna and system integration.

       For example, Monza s6-c label chip provides high performance and data integrity for large-scale intelligent applications. It includes the characteristics of automatic performance adjustment, self diagnosis and durable structure. It not only improves the quality and reading performance of the label, but also reduces the cost of label application. It is suitable for single tier applications in retail, medical, ticketing and other applications.

       4. Fudan Microelectronics

       Based on years of technical accumulation in the field of RF and storage, the UHF series chips of Shanghai Fudan Microelectronics Group Co., Ltd. have the characteristics of high RF reading and writing sensitivity, good compatibility and high memory reliability. They can be widely used in the fields of material management, transportation, material flow express, personnel management, access control management and so on.

       The working frequency band of ultra-high frequency RFID tag chip of Fudan Microelectronics is 840mhz to 960MHz. This series of chips comply with domestic standards GB / t29768 and gjb7377 1, and the label chip in accordance with the international iso18000-6c protocol. Ordinary version without encryption algorithm and secure version chip with encryption algorithm can be provided respectively.

       5. Jiangsu core cloud technology

       Jiangsu core cloud technology is an electronic technology company rooted in China and driven by technological innovation. Relying on the highly competitive returnee technology team, it has made breakthroughs in chip design and key technology fields, built a collaborative innovation ecology of cloud applications, and participated in the global commercial competition of integrated circuits and electronic solutions. In addition to the ability of core cloud technology from chip to overall solution in the RFID field, the high-speed power line carrier communication (HPLC) chip and module independently developed by core cloud technology have been widely used in the field of smart meter reading of the State Grid, which highly meets the requirements of "full centralized reading, full cost control and active monitoring" of power consumption information collection of the smart grid. At the same time, the 8-channel 16bit ADC chip independently developed by core cloud technology is mainly used for power grid relay protection devices and automation equipment. It has passed the system verification of relevant industrial units of the State Grid and entered the actual hanging test stage of the system.

       The overall solution of core cloud technology RFID products covers cloud, pipe and end, and constructs a three-dimensional internet of things connection management and control system. The products mainly include RFID passive UHF electronic tag chip, passive UHF electronic tag, UHF handheld reader, UHF RFID channel door, cloud platform information system, etc. At present, the products and solutions have been applied in the fields of asset management, intelligent warehousing, mobile transportation inspection and so on.

 ▲Application of RFID technology in intelligent patrol inspection of asset management

       6. Shenzhen Yuanwang Valley

       Shenzhen yuanwanggu Information Technology Co., Ltd. has built a world leading RFID product performance test center, which can provide RFID technology, products and solution services for large-scale Internet of things construction, and has more than 100 kinds of RFID products in 6 series. It focuses on the three strategic industries of railway, books and retail, and provides high-performance RFID products and solutions for textile washing, smart tourism, tobacco and alcohol management, intelligent transportation and other fields.

       Yuanwang valley began to develop the special chip for truck electronic label in 1995. At present, it has developed the first generation of special chip for truck electronic label with completely independent intellectual property rights, which also makes the truck electronic label have a "Chinese core". Because of this "China core", the United States was forced to reduce the original price of $150 truck electronic labels to more than $20.

       Antenna:

       RFID antenna is also divided into tag antenna and reader antenna. According to different applications, RFID tags may need to be attached to different types and shapes of objects, or even embedded into the object. Tag antenna and reader antenna also bear the functions of receiving energy and transmitting energy respectively. These factors put forward strict requirements for the design of antenna.

       1. Laird Tech

       Laird Technology Group is a world-famous company that designs and manufactures electromagnetic shielding materials, thermal conductive interface materials and wireless antenna products. Its products are widely used in telecommunications, data communication, mobile phones, computers, general electronic devices, network equipment, aerospace, national defense, automobile and medical equipment.

       2. Innell Technology

       Shenzhen yingneier Technology Co., Ltd. is a technology enterprise specializing in the design, development, production and sales of RFID antenna. It mainly provides RFID tag enterprises with: pet aluminum etching antenna, pet copper etching antenna, NFC circuit board coil antenna, anti metal interference antenna, all kinds of PCB high-precision special-shaped antenna and antenna design and development on behalf of customers. It can provide fast and high-quality high-frequency and ultra-high-frequency etching antennas.

       3. AoXin Technology

       Foshan AoXin Technology Co., Ltd. integrates R & D, production and sales. It is good at card reader antennas in radio frequency applications, mainly engaged in 4G / LTE, 3G, WiFi, WiMAX, RFID, VHF / UHF, TV, MIMO, CPE, GPS, GSM, CDMA, etc.

       Equipment:

       RFID devices include readers and tags. RFID readers can identify and track RFID tags by using electromagnetic fields, and obtain the electronic information stored in these tags.

       1. Honeywell scanning and mobile technology (HSM)

       Honeywell scanning and mobile technology department is subordinate to Honeywell automation control system group. As a professional bar code scanner manufacturer, its products include laser bar code scanner, image bar code scanner, OEM scanning engine, mobile data terminal and bar code detector.

       2. Zebra technologies

       Zebra technology company began to develop RFID printers in 1999 and successfully developed high-frequency and UHF RFID printers. Zebra technology products and solutions are widely used in many industries around the world and are suitable for various applications. For example, bar code wristbands and clinical sample collection are used to improve the medical safety of patients; Print receipts using mobile devices to speed up checkout; Simplify warehousing business process; And use real-time information to add new analytical data to professional competitions and entertainment programs.

       3.ThingMagic

       Thingmagic is a world-renowned RFID equipment manufacturer, founded in 2000 and headquartered in Boston, USA. It focuses on the R & D and production of reader, sensor and embedded system technology. Its fixed reader M6 and intelligent reader Astra have been widely used in the market, and have high popularity and share in the world. They are widely used in vehicle management, personnel management, supply chain management and other occasions.

       RFID technology has been widely used in asset management, retail, logistics, clothing, transportation, medical treatment, identity recognition, financial payment and other fields, and plays an important role in the national economy and people's livelihood. With the development and promotion of Internet of things technology, RFID, as one of the key technologies in the perception layer, has been widely usedAndUsher in a period of greater opportunities.Taking the application of RFID in asset management as an example, let's take a look at the specific application of RFID technology in the Internet of things asset management project.

       asFigure belowAs shown in, the Internet of things asset management system based on RFID technology can generally be divided into three-tier architecture:

▲Application architecture of Internet of things system based on RFID Technology

       Information acquisition layer：Specific equipment includes the functions of storing, collecting and reporting the information of RFID tags equipped with assets through RFID electronic tags, RFID handheld readers and RFID channel doors, and managing and identifying equipment assets through the uniqueness of RFID tag serial number.

       Data transport layer：The asset information collected by RFID reading and writing equipment can be transmitted to the background system management platform through mobile network, WiFi, Ethernet, etc.

Business management：Deploy the cloud management platform to manage various equipment resources in the system, and effectively analyze the data, so as to judge the processes such as goods ex warehouse, warehousing, warehouse transfer and inventory.At the same time, corresponding report details can be generated and processed in the system.

       Through the application of the asset management system based on the Internet of things, realize the information, intelligent and standardized management of assets, build the asset life cycle management system and multi-level security protection measures, realize the consistency of accounts, cards and things, improve the efficiency of asset inventory, realize the real-time monitoring of asset circulation, and actively report the abnormal status of assets in and out of the warehouse, Greatly improve the maintenance efficiency of daily work.At the same time, the business system carefully analyzes the data, comprehensively grasps the asset business information, effectively excavates the data value, improves the data application level, provides more valuable information for asset management decisions, and comprehensively improves the asset management level.

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