Radio Frequency Identification Technology and Its Application Development Trend

Jacktang

Radio Frequency Identification Technology and Its Application Development Trend [Copy link]

Radio Frequency Identification (RFID), or RFID, is a non-contact automatic identification technology that has been around since the 1990s. It uses radio frequency to conduct non-contact two-way communication to automatically identify the target object and obtain relevant data. It has many advantages, such as high accuracy, strong adaptability to the environment, strong anti-interference, and fast operation.

Among the currently commonly used automatic identification technologies, barcodes and magnetic cards have lower costs, but are easily worn and have very small data volumes; contact IC cards are slightly more expensive, have larger data storage volumes, and are more secure, but are also easily worn and have a short lifespan; radio frequency cards achieve contactless operation, are easy to use, have no mechanical wear, have a long lifespan, do not require visible light sources, have good penetration, are highly resistant to pollution, and have strong durability. Moreover, they can work in harsh environments, have low environmental requirements, have a long reading distance, can obtain data without contacting the target, support writing data, do not need to re-make new labels, can be reused, and use anti-collision technology, can identify high-speed moving objects, and can identify multiple radio frequency cards at the same time.

In recent years, radio frequency identification technology has developed rapidly at home and abroad. There are many types of RFID products. World-renowned manufacturers such as TI, Motorola, Philips, Microchip, etc. all produce RFID products, and each has its own characteristics and forms its own series. RFID has been widely used in many fields such as industrial automation, commercial automation, transportation control and management, such as traffic monitoring systems for cars or trains, automatic toll collection systems on highways, item management, assembly line production automation, access control systems, financial transactions, warehouse management, animal husbandry management, vehicle anti-theft, etc. With the decline in costs and the implementation of standardization, the comprehensive promotion and widespread application of RFID technology will be an irreversible trend.

1 Radio Frequency Identification Technology
1.1 Composition and Working Principle of RFID System

The composition of RFID system varies depending on the application, but it is basically composed of three parts: electronic tag (Tag), reader (Reader) and data exchange and management system (Processor). Electronic tag (or radio frequency card, transponder, etc.) is composed of coupling elements and chips, which are full of encryption logic, serial EEPROM (electrically erasable and programmable read-only memory), microprocessor CPU, radio frequency transceiver and related circuits. Electronic tag has the functions of intelligent reading and writing and encrypted communication. It exchanges data with the reading and writing equipment through radio waves, and the working energy is provided by the radio frequency pulses emitted by the reader. Reader, sometimes also called query, reader or reader, is mainly composed of wireless transceiver module, antenna, control module and interface circuit. Reader can transmit the host's read and write commands to the electronic tag, encrypt the data sent from the host to the electronic tag, decrypt the data returned by the electronic tag and send it to the host. The data exchange and management system mainly completes the storage and management of data information, read and write control of the card, etc.

The working principle of the RFID system is as follows: the information to be sent by the reader is encoded and loaded on a carrier signal of a certain frequency and sent out through the antenna. The electronic tag entering the working area of the reader receives this pulse signal, and the relevant circuits in the chip in the card modulate, decode and decrypt this signal, and then judge the command request, password, authority, etc. If it is a read command, the control logic circuit reads the relevant information from the memory, encrypts, encodes, and modulates it, and then sends it to the reader through the antenna in the card. The reader demodulates, decodes, and decrypts the received signal and sends it to the central information system for relevant data processing; if it is a write command to modify the information, the internal charge pump caused by the relevant control logic increases the working voltage, and provides the content in the erased EEPROM for rewriting. If it is judged that the corresponding password and authority do not match, an error message is returned.

In the RFID system, the reader must generate a suitable energy field within the readable distance to excite the electronic tag. Under the current radio frequency constraints, the isotropic effective radiated power is limited to 500mW in most parts of Europe. Such radiated power at 870MHz can reach approximately 0.7 meters. In the United States, Canada and some other countries, the unauthorized radiation constraint is an isotropic radiated power of 4W, which will reach a reading distance of 2 meters. With authorization, emitting 30W of power in the United States will increase the reading area to about 5.5 meters.

1.2 Classification of RFID Technology

There are four common classification methods for RFID technology:

According to the different working frequencies of electronic tags, they can usually be divided into low frequency (30kHz~300kHz), medium frequency (3MHz~30MHz) and high frequency systems (300MHz~3GHz). Common working frequencies of RFID systems include low frequency 125kHz, 134.2kHz, medium frequency 13.56MHz, high frequency 860MHz~930MHz, 2.45GHz, 5.8GHz, etc. The characteristics of low frequency systems are that the amount of data stored in electronic tags is small, the reading distance is short, the shape of electronic tags is diverse, and the reading antenna is not directional. It is mainly used in short-distance, low-cost applications, such as most access control, campus cards, gas meters, water meters, etc.; medium frequency systems are used in application systems that need to transmit large amounts of data; the characteristics of high frequency systems are that the cost of electronic tags and readers is high, the amount of data stored in the tags is large, the reading distance is far (up to more than ten meters), it can adapt to high-speed movement of objects, and has good performance. Both reading antennas and electronic tag antennas have strong directionality, but their wide beam directions are narrow and their prices are high. They are mainly used in situations that require a longer reading and writing distance and a higher reading and writing speed, and are mostly used in train monitoring, highway toll collection and other systems.

According to the different electronic tags, they can be divided into read-write cards (RW), write-once-read-many cards (WORM) and read-only cards (RO). RW cards are generally much more expensive than WORM cards and RO cards, such as phone cards and credit cards; WORM cards are cards that users can write once, and the data cannot be changed after writing, which is cheaper than RW cards; RO cards have a unique number that cannot be changed, ensuring security.

According to whether the electronic tag is active or passive, it can be divided into active and passive. Active electronic tags use the energy of the current in the card and have a long identification distance of up to ten meters, but their lifespan is limited (3 to 10 years) and their price is relatively high; passive electronic tags do not contain batteries. After receiving the microwave signal from the reader (reading device), they use the electromagnetic waves emitted by the reader to provide energy. They are generally maintenance-free, light in weight, small in size, long in life, and relatively cheap, but their transmission distance is limited, generally tens of centimeters, and require the reader to have a large transmission power.

According to the different modulation methods of electronic tags, they can also be divided into active tags and passive tags. Active electronic tags use their own radio frequency energy to actively send data to the reader/writer. They are mainly used in applications with obstacles and at a long distance (up to 30 meters). Passive electronic tags use modulation scattering to transmit data. They must use the carrier of the reader/writer to modulate their own signals. They are suitable for use in access control or transportation applications.

1.3 RFID Technology Standards

At present, the commonly used RFID international standards are mainly ISO11784 and ISO11785 for animal identification, ISO10536 (Close coupled cards), ISO 15693 (Vicinity cards), ISO14443 (Proximity cards) for contactless smart cards, ISO 10374 for container identification, etc. At present, there are three well-known organizations that formulate RFID standards internationally: ISO, EPC global led by the United States, and Ubiquitous ID Center in Japan. These three organizations have their own goals and development plans for RFID technology application specifications. The following is a brief introduction to several common standards.

ISO 11784 and ISO 11785 technical standards:

ISO 11784 and ISO

11785 respectively stipulates the code structure and technical criteria for animal identification. The standard does not specify the style and size of the transponder, so it can be designed into various forms suitable for the animals involved, such as glass tubes, health tags or collars. The code structure is 64 bits, of which 27 to 64 bits can be defined by each country. The technical criteria stipulate the data transmission method and reader specifications of the transponder. The operating frequency is 134.2kHz, and the data transmission mode is full-duplex and half-duplex. The reader data is represented by differential biphase code, and the transponder uses FSK modulation and NRZ encoding. Due to the long transponder charging time and operating frequency limitations, the communication rate is low.

ISO 10536, ISO 15693 and ISO14443 technical standards:

The ISO 10536 standard was developed between 1992 and 1995. Due to the high cost of this card and few advantages over contact IC cards, this card has never been sold on the market. The ISO 14443 and ISO 15693 standards began operation in 1995 and were completed after 2000. Both use 13.56MHz alternating signals as carrier frequencies. ISO 15693 has a longer reading and writing distance, while ISO 14443 has a slightly shorter reading and writing distance, but is more widely used. The current second-generation electronic ID card standard is the ISO 14443 TYPE B protocol. ISO 14443 defines two types of protocols, TYPE A and TYPE B, with a communication rate of 106kbit/s. The main difference between them is the modulation depth of the carrier and the bit encoding method. TYPE A uses Manchester encoding with on-off keying, and TYPE B uses NRZ-L BPSK encoding. Compared with TYPE A, TYPE B has the advantages of uninterrupted energy transmission, higher speed and strong anti-interference ability. The core of RFID is anti-collision technology, which is also the main difference from contact IC card. ISO 14443-3 specifies the anti-collision mechanism of TYPE A and TYPE B. The principles of the anti-collision mechanism of the two are different. The former is based on the bit collision detection protocol, while the TYPE B communication series command sequence completes the anti-collision. ISO 15693 uses a round-robin mechanism and time-sharing query to complete the anti-collision mechanism. The anti-collision mechanism makes it possible to operate multiple cards in the read-write area at the same time, which not only facilitates the operation but also improves the speed of operation.

ISO 18000 Technical Standards:

ISO 18000 is a series of standards. This standard is the newest standard because it can be used in the supply chain of goods, and some of the standards are still being formed. ISO 18000-6 is basically a specification that integrates the reducer specifications of some existing RFID manufacturers and the tag architecture requirements proposed by EAN-UCC. ISO 18000 only specifies the air interface protocol and has no restrictions on data content and data structure, so it can be used for EPC.

2 Introduction to Typical RFID Products
RFID products can be divided into identity recognition ID cards, consumer ICs, logistics tag cards, and long-distance recognition cards according to their functions. At present, the RFID products of various manufacturers have different focuses in terms of functions; the ID cards of Swiss EM Company are mainly used for identity recognition, the Mifare One cards of Dutch Philips Company are mainly used for consumption, the tag cards of American TI Company are mainly used for logistics, and the long-distance cards of Swedish TagMaster Company are mainly used for long-distance recognition of parking personnel and materials, etc.

3 Application and Development Trends
Currently, RFID application and development are facing several key issues: standards, cost, technology and security.

3.1 Standards

At present, the industry standards and related product standards are not unified, and the world has not yet formally formed a unified (including various frequency bands) international standard for electronic standard signatures. The inconsistency of standards (especially the standards for data format definition) is an important factor restricting the development of RFID, and the standard issue of data format involves the use and security of each country. The inconsistency of standards also makes the RFID products launched by various manufacturers incompatible with each other, which is bound to hinder the interoperability and development of RFID products in the future. Therefore, how to make these standards compatible with each other and allow an RFID product to circulate smoothly in the private sector is an important and urgent issue at present. At present, many countries are rushing to formulate their own standards, and my country's electronic tag technology is still in the research and development stage.

3.2 Cost

At present, the lowest price of an electronic tag in the United States is about 20 cents, which is not applicable to some low-value single items. Only when the price of electronic tags drops below 10 cents can they be widely used in boxes and packages of goods. With the continuous improvement of technology and its increasing promotion in major industries, the manufacturing costs of various components of RFID, including electronic tags, readers and antennas, are expected to be greatly reduced.

3.3 Technology

Although the individual technologies of RFID electronic tags have become mature, the overall product technology is still not mature enough and there is still a high error rate (the rate of RFID misreading is sometimes as high as 20%). A large number of technical difficulties still need to be overcome in integrated applications.

3.4 Security

The currently widely used passive RFID system does not have a very reliable security mechanism and cannot keep data confidential. RFID data is also vulnerable to attacks, mainly because the RFID chip itself and the chip in the process of reading or writing data are easily exploited by hackers. In addition, there is also the problem of recognition rate. Due to the great interference of liquids and metal mouths on radio signals, the accurate recognition rate of RFID tags is currently only about 80%, which is still a certain distance from the maturity required for large-scale practical applications.

Generally speaking, RFID technology has gradually developed into an independent interdisciplinary professional field, which integrates a large number of technologies from different professional fields: such as high-frequency technology, electromagnetic compatibility, semiconductor technology, data protection and cryptography, telecommunications, manufacturing technology and many professional fields. The main aspects in which RFID technology can be applied and exerted include saving labor costs, improving operation accuracy, speeding up processing speed, and effectively tracking logistics dynamics. At present, RFID technology has been widely used in many fields such as industrial automation, commercial automation, and transportation control management. In early November 2004, a technology status survey report completed by the American magazine "VAR Vusiness" rated the "seven hot technology trends" in 2005, among which radio frequency identification technology (RFID) was regarded as a breakthrough technology in the technology industry in 2005. Wal-Mart and the US Department of Defense are promoting the plan of fully introducing RFID, and many high-tech companies are also developing RFID-specific software and hardware, including Intel, Microsoft, Oracle and SUN. ABI estimates that by 2008, sales of RFID tags, readers, and related software and services are expected to increase to $3 billion, and the RFID technology market will have a trillion-dollar market space in the next five years.