What is RFID?

Catalog

Ⅰ RFID Overview

RFID is a type of automatic identification technology that uses wireless radio frequency to carry out non-contact two-way data communication and uses radio frequency to read and write recording media (electronic tags or radio frequency cards), so as to achieve the purpose of identifying goals and data exchange. It is considered to be one of the most promising information technologies in the 21st century.

Radio frequency identification technology uses radio wave non-contact rapid information exchange and storage technology, combines wireless communication with data access technology, and then connects to the database system to achieve non-contact two-way communication, thereby achieving the purpose of identification and used for data exchange. In the identification system, the reading and writing, and communication of electronic tags are realized through electromagnetic waves. According to the communication distance, it can be divided into near-field and far-field. For this reason, the data exchange mode between the read/write device and the electronic tag is also divided into load modulation and backscatter modulation.

Ⅱ RFID development process

1940-1950: Due to the development and progress of radar technology, RFID technology was derived, and the theoretical basis of RFID was born in 1948.

1950-1960: People began to explore RFID technology, but did not leave the laboratory research.

1960-1970: Related theories continued to develop, and the system began to be used in practice.

1970-1980: RFID technology was continuously updated, product research gradually deepened, and RFID testing began to accelerate further.

1980-1990: RFID technology and related products were developed and applied in the market, and applications in various fields appeared.

1990-2000: People began to pay attention to the standardization of RFID, and RFID systems can be seen in many areas of life.

After 2000: People generally recognized the importance of standardization issues, and the types of RFID products were further enriched and developed. No matter active, passive, or semi-active electronic tags began to develop, related production costs were further reduced, and the application fields gradually increased.

Today, the technical theory of RFID has been further enriched and developed. People have developed single-chip electronic tags, multi-electronic tag reading, wireless readable and writable, and RFID technology that adapts to high-speed moving objects has continued to develop, and related products have also been developed.

Ⅲ RFID working principle

The basic working principle of RFID technology is not complicated: after the tag enters the reader, it receives the radio frequency signal from the reader and uses the energy obtained by the induced current to send out the product information stored in the chip (Passive Tag ), or the tag actively sends a signal of a certain frequency (Active Tag), the reader reads and decodes the information, and then sends it to the central information system for relevant data processing.

RFID basic principles and basic composition

A complete RFID system is composed of a reader and an electronic tag, which is a so-called transponder and an application software system. Its working principle is that the reader emits radio wave energy of a specific frequency to the drive circuit that sends out the internal data. At this time, the Reader receives and interprets the data in sequence and sends them to the application program for corresponding processing.

From the perspective of the communication and energy-sensing methods between the RFID card reader and the electronic tag, it can be roughly divided into two types: inductive coupling and backscatter coupling. Generally, low-frequency RFID mostly adopts the first method, and high-frequency RFID mostly adopts the second method.

The reader can be a read or read/write device depending on the structure and technology used, and it is the information control and processing center of the RFID system. The reader usually consists of a coupling module, a transceiver module, a control module, and an interface unit. The reader and the tag generally use half-duplex communication to exchange information, and the reader provides energy and timing to the passive tag through the coupling. In practical applications, management functions such as the collection, processing, and remote transmission of object identification information can be further realized through Ethernet or WLAN.

Ⅳ RFID components

The complete RFID system consists of three parts: Reader, Tag, and data management system.

1. Reader

The reader is a device that reads the information in the tag or writes the information that the tag needs to store into the tag. Depending on the structure and technology used, the reader can be a read/write device, which is the information control and processing center of the RFID system. When the RFID system is working, the reader sends radio frequency energy in an area to form an electromagnetic field, and the size of the area depends on the transmit power. The tag in the coverage area of the reader is triggered to send the data stored in it, or modify the data stored in it according to the instructions of the reader, and can communicate with the computer network through the interface. The basic composition of the reader usually includes a transceiver antenna, frequency generator, phase-locked loop, a modulation circuit, microprocessor, memory, demodulation circuit, and peripheral interface composition.

(1) Transceiver antenna: Send radio frequency signals to the tag, and receive the response signal and tag information returned by the tag.

(2) Frequency generator: Generates the operating frequency of the system.

(3) Phase-locked loop: Generate the required carrier signal.

(4) Modulation circuit: Load the signal sent to the tag to the carrier wave and send it out by the radio frequency circuit.

(5) Microprocessor: Generates the signal to be sent to the label, decodes the signal returned by the label, and sends the decoded data back to the application program. If it is an encrypted system, a decryption operation is also required.

(6) Memory: store user programs and data.

(7) Demodulation circuit: demodulate the signal returned by the tag and deliver it to the microprocessor for processing.

(8) Peripheral interface: to communicate with the computer.

2. Electronic tags

The electronic tag consists of a transceiver antenna, AC/DC circuit, demodulation circuit, logic control circuit, memory, and modulation circuit.

RFID Tag

(1) Transceiver antenna: Receive the signal from the reader and send the required data back to the reader.

(2) AC/DC circuit: Utilize the electromagnetic field energy emitted by the reader, output by the voltage regulator circuit to provide a stable power supply for other circuits.

(3) Demodulation circuit: Remove the carrier from the received signal and demodulate the original signal.

(4) Logic control circuit: decode the signal from the reader, and send back the signal according to the requirements of the reader.

(5) Memory: As a location for system operation and storage of identification data.

(6) Modulation circuit: The data sent by the logic control circuit is loaded to the antenna and sent to the reader after the modulation circuit.

Ⅴ RFID classification

Radio frequency identification technology can be divided into three categories based on the power supply mode of its tags, namely passive RFID, active RFID, and semi-active RFID.

1. Passive RFID

Among the three types of RFID products, passive RFID is the earliest and the most mature, and its application is also the most extensive. In passive RFID, the electronic tag completes the information exchange by receiving the microwave signal transmitted from the radio frequency identification reader and obtaining energy through the electromagnetic induction coil to power itself for a short time. Because the power supply system is omitted, the volume of the passive RFID product can reach the order of centimeters or even smaller. Its own structure is simple, the cost is low, the failure rate is low, and the service life is long. But as a price, the effective recognition distance of passive RFID is usually short, and it is generally used for close-range contact recognition. Passive RFID mainly works in the lower frequency band 125KHz, 13.56MKHz, etc. Its typical applications include: bus cards, second-generation ID cards, canteen meal cards, etc.

2. Active RFID

Active RFID has not been around for a long time, but it has played an indispensable role in various fields, especially in the electronic non-stop toll collection system of highways. Active RFID is powered by an external power source and actively sends signals to the radio frequency identification reader. Its volume is relatively large. But it also has a longer transmission distance and higher transmission speed. A typical active RFID tag can establish contact with a radio frequency identification reader from a hundred meters away, and the read rate can reach 1,700 read/sec. Active RFID mainly works in higher frequency bands such as 900MHz, 2.45GHz, 5.8GHz, and has the function of identifying multiple tags at the same time. The long-distance and high-efficiency of active RFID make it indispensable in some radio frequency identification applications that require high performance and a large range.

3. Semi-active RFID

Passive RFID itself does not supply power, but the effective identification distance is too short. Active RFID has a long enough recognition distance, but requires an external power source and is relatively large. The semi-active RFID is the product of compromise for this contradiction. Semi-active RFID is also called low-frequency activation trigger technology. Under normal circumstances, semi-active RFID products are in a dormant state and only supply power to the part of the tag that holds the data, so the power consumption is small and can be maintained for a long time. When the tag enters the recognition range of the RFID reader, the reader first activates the tag in a small range with a 125KHz low-frequency signal to make it enter the working state, and then transmits information to it through 2.4GHz microwave. In other words, first, use low-frequency signals for precise positioning, and then use high-frequency signals to quickly transmit data. Its general application scenario is: in a large range covered by a high-frequency signal, multiple low-frequency readers are placed in different positions to activate semi-active RFID products. This not only completes the positioning but also realizes the collection and transmission of information.

Ⅵ RFID advantages and disadvantages

1.Advantages

Radio frequency identification technology can be widely used in many industries and fields, and it must have its "excellence".

In terms of its external manifestations, the carrier of radio frequency identification technology generally has the characteristics of waterproof, antimagnetic, and high-temperature resistance to ensure that the radio frequency identification technology is stable in the application. In terms of its use, RFID has advantages in real-time updating of data, storage of information, service life, work efficiency, and safety. Radio frequency identification can update existing data more conveniently under the premise of reducing human, material, and financial resources, making work more convenient. Radio frequency identification technology stores information based on computers, etc., up to several megabytes, and can store a large amount of information. To ensure the smooth progress of work, radio frequency identification technology has a long service life, as long as the staff pays attention to protection when using it, it can be reused. Radio frequency identification technology has changed the inconvenience of information processing in the past and achieved multiple goals at the same time. Identification greatly improves work efficiency and is also equipped with password protection, which is not easy to be forged and has high security. The technology similar to radio frequency identification technology is traditional bar code technology. Traditional bar code technology is inferior to radio frequency identification technology in terms of updating information, storing information, service life, work efficiency, and safety, and cannot adapt well to our country. The current needs of social development are also difficult to meet the needs of industries and related fields.

2.Disadvantages

(1) Technological maturity is not enough. RFID technology has appeared for a short time and is not very mature in technology. Due to the retro-reflective characteristics of UHF RFID electronic tags, it is difficult to apply them to commodities such as metals and liquids.

(2) High cost. Compared with ordinary barcode labels, the price of RFID electronic tags is higher, which is dozens of times that of ordinary barcode labels. If they are used in large quantities, the cost will be too high, which greatly reduces the enthusiasm of the market to use RFID technology.

(3) The security is not strong enough. The security problem faced by RFID technology is mainly manifested in the illegal reading and malicious tampering of RFID electronic tag information.

(4) The technical standards are not uniform.

Ⅶ RFID applications

RFID vehicle management

1. Logistics

Logistics warehousing is one of the most potential application areas of RFID. International logistics giants such as UPS, DHL, Fedex, etc. are actively experimenting with RFID technology in order to improve their logistics capabilities on a large scale in the future. Applicable processes include cargo tracking in the logistics process, automatic information collection, warehousing management applications, port applications, postal parcels, express delivery, etc.

2. Transportation

There have been many successful cases in taxi management, bus terminal management, and railway locomotive identification.

3. Identification

RFID technology is widely used in personal identification documents due to its fast reading and difficulty to forge. Such as the development of the electronic passport project, ID card, student card, and other various electronic documents.

4. Anti-counterfeiting

RFID has the characteristics of being difficult to forge, but how to apply it to anti-counterfeiting still requires active promotion by the government and enterprises. The applicable fields include the anti-counterfeiting of valuables (tobacco, alcohol, medicine) and the anti-counterfeiting of tickets.

5. Asset management

It can be applied to the management of all kinds of assets, including valuables, items with large quantities and high similarity, or dangerous goods, etc. As the price of tags decreases, RFID can manage almost all items.

6. Food

It can be applied to the management of fruits, vegetables, fresh food, etc. The application in this field requires innovation in label design and application mode.

7. Information statistics

With the use of radio frequency identification technology, information statistics has become a simple and fast task. The query software of the archives information management platform sends out the statistical inventory signal, and the reader quickly reads the data information and related storage information of the archives, and intelligently returns the acquired information and the information in the central information database for proofreading. For example, for files that cannot be matched, the manager will use the reader to carry out on-site verification, adjust the system information and on-site information, and then complete the information statistics work.

8. Check the application

When querying file information, the file manager uses the query management platform to find the file number. The system reads the data in the central information database according to the file number. After verification, it sends out the file-out signal, and the storage management platform intelligently recognizes the file. The function module will combine the file number corresponding to the relevant storage number to find out the specific location of the file. After the manager sends out the file out-of-warehouse signal, the indicator light on the storage location will immediately light up. When the data is out of the library, the RFID reader will feedback the acquired information to the management platform. The manager will verify it again. Moreover, the system will record the time when the information is out of the library. If the feedback file does not match the query file, the alarm module in the security management platform will transmit an abnormal warning.

9. Security control

The security control system can realize the functions of timely monitoring and abnormal alarm of the archives, so as to avoid the destruction and theft of the archives. When archives are borrowed and returned, especially physical archives, they are often used for exhibitions, evaluation and inspection, etc. The manager carefully checks the returned archives and verifies with the information before the archives are lent, and can find out whether the archives are damaged or missing in time.