The definition, composition and characteristics of RFID

Radio Frequency Identification (RFID), also known as Radio Frequency Identification (RFID), is a communication technology that uses radio signals to identify specific targets and read and write related data without the need to identify mechanical or optical contact between the system and a particular target. . For radio frequency, it is usually microwave, 1-100GHz, suitable for short-distance identification communication. RFID readers are also mobile and fixed. At present, RFID technology is widely used, such as: library, access control system, food safety traceability.

Conceptually, RFID is similar to bar code scanning. For bar code technology, it attaches the encoded bar code to the target and uses a dedicated scanning reader to transmit information from strip magnet to scan read and write using optical signals. RFID uses a dedicated RFID reader and a dedicated RFID tag that attaches to the target, using frequency signals to transmit information from the RFID tag to the RFID reader.

Radio Frequency Identification (RFID) is a wireless communication technology that uses radio signals to identify specific targets and read and write related data without the need to identify mechanical or optical contact between the system and a particular target.

RFID technology is a non-contact automatic identification technology, which uses radio frequency signals to realize contactless information transmission through spatial coupling (alternating magnetic field or electromagnetic field) and achieve the purpose of identification through the transmitted information. The identification work can be done without manual intervention. In a variety of harsh environments. RFID technology can recognize high-speed moving objects and recognize multiple labels at the same time, which is quick and easy to operate. "Contactless" means that it can identify a specific target by radio signals and read and write relevant data without having to identify mechanical or optical contact between the system and a particular target.

The radio's signal is transmitted from the tag attached to the item by an electromagnetic field that is modulated into a radio frequency to automatically identify and track the item. Some tags receive energy from the electromagnetic field emitted by the recognizer when they are recognized, and do not require a battery. The tag itself has a power source and can actively emit radio waves (electromagnetic fields that are modulated into radio frequencies). The tag contains electronically stored information that can be identified within a few meters. Unlike barcodes, RF tags do not need to be within the line of sight of the recognizer, but can also be embedded within the object being tracked.

Radio frequency identification technology is used in many industries. Attaching the label to a car that is in production, the factory can easily track the progress of the car on the production line. The warehouse can track where the medicine is located. RF tags can also be attached to livestock and pets to facilitate positive identification of livestock and pets (positive identification means preventing several animals from using the same identity). The RFID-enabled identification card allows employees to access the locked building section, and the RF transponder on the car can also be used to collect the toll road and parking lot. Some RF tags are attached to clothing, personal belongings, and even implanted in the human body. Because this technology may read personal information without my permission, this technology may also infringe on personal privacy concerns.

Transponder: consists of an antenna, a coupling element and a chip. Generally, the tag is used as a transponder. Each tag has a unique electronic code attached to the object to identify the target object.

Reader: A device consisting of an antenna, a coupling element, a chip, and reading (and sometimes writing) tag information. It can be designed as a handheld rfid reader or a fixed reader.

Application software system: It is application layer software, which mainly processes the collected data and uses it for people.

The composition of the RFID system

The RFID system should include at least two parts, one is the reader, and the other is the electronic tag (or RF card, transponder, etc., collectively referred to as the electronic tag). Also include antennas, mainframes, etc. In the specific application process of RFID system, the composition of the system will be different according to different application purposes and application environment. However, from the working principle of RFID system, the system generally consists of signal transmitter, signal receiver, transmission and reception. The antenna is composed of several parts. The following are explained separately:

1 signal transmitter

In RFID systems, signal transmitters exist in different forms for different application purposes, typically in the form of tags (TAG). The tag is equivalent to the bar code symbol in the bar code technology, and is used to store the information that needs to be identified and transmitted. In addition, unlike the bar code, the tag must be able to actively transmit the stored information automatically or under the action of an external force.

2 signal receiver

In RFID systems, signal receivers are generally referred to as readers. The complexity of the reader is significantly different depending on the type of tag supported and the function being completed. The basic function of the reader is to provide a way to transfer data with the tag. In addition, the reader provides fairly complex signal state control, parity error checking and correction functions. In addition to storing the information to be transmitted, the tag must also contain certain additional information, such as error check information. The identification data information and the additional information are compiled according to a certain structure and sent out in a specific order. The reader controls the transmission of the data stream by receiving additional information. Once the information arriving at the reader is correctly received and deciphered, the reader determines whether the transmitter needs to retransmit the transmitted signal once, or knows that the transmitter stops signaling, which is the "command response protocol". Using this protocol, even if you read multiple tags in a short time and in a small space, you can effectively prevent the "spoofing problem".

3 programmer

A programmer is only required for a readable and writable label system. A programmer is a device that writes data to a tag. The programmer writes the data in general, which is done offline (OFF-LINE), that is, the data is written in the label in advance, and the label is directly attached to the identified item when the application is started. There are also some RFID applications where writing data is done online (ON-LINE), especially when handled as an interactive portable data file in a production environment.

4 antenna

The antenna is a transmitting and receiving device that transmits data between the tag and the reader. In practical applications, in addition to system power, the shape and relative position of the antenna will also affect the transmission and reception of data. Professionals are required to design and install the antenna of the system.

Radio frequency technology

The most important advantage of RFID systems is non-contact identification, which penetrates the harsh environment of snow, fog, ice, paint, dirt and bar codes that are not usable, and is extremely fast to read, in most cases less than 100 milliseconds. The ability to write to an active RFID system is also an important advantage. Can be used for interactive services such as process tracking and maintenance tracking.

The main problem that constrains the development of RFID systems is the incompatibility standard. The major manufacturers of RFID systems provide dedicated systems, resulting in different applications and different industries using different vendors' frequency and protocol standards. This confusion and separatism has restricted the growth of the entire RFID industry. Many European and American organizations are working on this issue and have achieved some results. Standardization will certainly stimulate the substantial development and wide application of radio frequency identification technology.

applicability

The essence of logistics management is to achieve the two purposes of reducing costs and improving service levels through the management of the whole process of logistics. How to get the right products at the right time and in the right place with the right cost and the right conditions has become the highest goal pursued by logistics companies. Generally speaking, the value of enterprise inventory accounts for about 25% of the total assets of the enterprise, accounting for more than 50% of the current assets of the enterprise. Therefore, the core of logistics management is the management of inventory in the supply chain.

The use of radio frequency identification technology in transportation management requires only the installation of electronic tags on the outer packaging of the goods, and the setting of readers at the transport checkpoints or transfer stations to realize the visual management of assets. At the same time, the owner can access the in-transit visualization webpage to understand the specific location of the goods according to the authority, which is of great significance to improve the service level of the logistics enterprise.

Performance characteristics

1. Quick scan. The RFID recognizer can recognize and read several RFID tags at the same time!

2. The size is small and the shape is diverse. RFID is not limited in size and shape on reading, and it does not need to match the fixed size and print quality of the paper for reading accuracy. In addition, RFID tags can be developed into smaller and more diverse forms for use in different products.

3. Anti-pollution ability and durability. Traditional bar code carriers are paper and are therefore susceptible to contamination, but RFID is highly resistant to substances such as water, oil and chemicals. In addition, since the bar code is attached to a plastic bag or an outer carton, it is particularly susceptible to breakage; the RFID tag is to store data in the chip and thus be protected from fouling.

4. Can be reused. Nowadays, barcode printing cannot be changed after it is printed. RFID tags can repeatedly add, modify, and delete data stored in RFID tags to facilitate information update.

5. Penetrating and barrier-free reading. In the case of being covered, RFID can penetrate non-metallic or non-transparent materials such as paper, wood and plastic, and can communicate transparently. The barcode scanner must be able to read the barcode at close range without object blocking.

6. The data has a large memory capacity. The capacity of the one-dimensional barcode is 50 Bytes, the maximum capacity of the two-dimensional barcode can be stored from 2 to 3000 characters, and the maximum capacity of the RFID is MegaBytes. With the development of the memory carrier, the data capacity has also been expanding. The amount of information that will be carried in future items will increase, and the demand for capacity expansion of the volume label will increase accordingly.

7. Security. Since RFID carries electronic information, its data content can be protected by passwords, making its content difficult to be forged and altered.

RFID has attracted attention because of its long-distance reading and high storage capacity. It not only helps a company to significantly improve the efficiency of goods and information management, but also allows sales companies and manufacturing companies to interconnect, so as to more accurately receive feedback, control demand information, and optimize the entire supply chain.