Radio frequency identification technology (RFID) is an emerging automatic identification technology developed in the 1980s. Radio frequency identification technology is a method that uses radio frequency signals to achieve non-contact information transmission through spatial coupling (alternating magnetic fields or electromagnetic fields) and passing them through. Information to achieve the purpose of identification technology. RFID is a simple wireless system with only two basic components that are used to control, detect and track objects. The system consists of an interrogator (or reader) and a number of transponders (or tags).
1, a radio frequency identification system concept <br> <br> RFID system by a radio frequency automatic identification system tags, readers and computer networks thereof. Generally, the reader emits energy in an area to form an electromagnetic field. When the radio frequency tag detects the signal of the reader when passing through this area, the stored data is sent. The reader receives the signal sent by the radio frequency tag, and decodes and verifies the accuracy of the data. To achieve the purpose of identification.
2. Technology
Initially in the technical field, transponders are electronic modules that can transmit information to reply information. In recent years, due to the rapid development of radio frequency technology, transponders have new claims and meanings, and are also called smart labels or tags. The reader (reader) of the RFID electronic elevator certificate wirelessly communicates with the RFID electronic tag through the antenna, and can read or write the tag identification code and memory data. A typical reader includes a high-frequency module (transmitter and receiver), a control unit, and a reader antenna.
RFID radio frequency identification is a non-contact automatic identification technology. It automatically identifies target objects and obtains relevant data through radio frequency signals. The identification work can be performed in various harsh environments without manual intervention. RFID technology can identify high-speed moving objects and can identify multiple labels at the same time. The operation is quick and easy.
Tag: Composed of a coupling element and a chip, each tag has a unique electronic code and is attached to the object to identify the target object.
Reader: A device that reads (sometimes writes) tag information and can be designed as a handheld rfid reader (eg C5000W) or a stationary reader.
Antenna: Passes RF signals between tags and readers.
3, the working principle <br> <br> label into the magnetic field, receives radio frequency signals emitted by interpretation, transmits the product information stored in the chip (PassiveTag, a passive tag or a passive tag) is obtained by virtue of the induced current energy, Or the tag actively sends a signal of a certain frequency (ActiveTag, active tag or active tag). After the reader reads the information and decodes it, it sends it to the central information system for data processing.
A complete RFID system is composed of three parts: a reader and a tag (TAG), a so-called transponder, and an application software system. The working principle is that Reader emits a specific frequency. The radio wave energy is given to the Transponder to drive the Transponder circuit to send the internal data. At this point, the Reader receives the decoded data in sequence and sends it to the application program for processing.
The communication between the RFID card reader and the electronic tag and the energy sensing method can be roughly divided into two types: Inductive Coupling and Backscatter Coupling. Most low-frequency RFIDs generally use the first type, while higher frequencies mostly use the second type.
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 is usually composed of a coupling module, a transceiver module, a control module, and an interface unit. Half-duplex communication is generally used for information exchange between the reader and the transponder, and the reader is coupled to the passive transponder to provide energy and timing. In practical applications, management functions such as collection, processing, and remote transmission of object identification information may be further implemented through Ethernet or WLAN. The transponder is the information carrier of the RFID system. At present, transponders are mostly composed of coupled originals (coils, microstrip antennas, etc.) and microchips constituting a passive unit.
4, work methods
The basic working methods of radio frequency identification systems are divided into Full Duplex and Half Duplex systems and Sequence (SEQ) systems. Full duplex means that the RFID tag and the reader can transmit information to each other at the same time. Half-duplex indicates that the RFID tag and the reader can transmit information in both directions, but can only transmit information in one direction at the same time.
In full-duplex and half-duplex systems, the RF tag's response is transmitted in the presence of electromagnetic fields or electromagnetic waves emitted by the reader. Since the signal of the radio frequency tag is weak at the receiving antenna compared to the signal of the reader itself, an appropriate transmission method must be used in order to distinguish the signal of the radio frequency tag from the signal of the reader. In practice, data transmission from RFID tags to readers typically uses load reflection modulation techniques to load RF tag data onto the reflected echo (especially for passive RF tag systems).
In contrast to the timing method, the radiated electromagnetic field from the reader is periodically switched off. These intervals are identified by the RF tag and used for data transmission from the RF tag to the reader. In fact, this is a typical way of working with radar. The disadvantage of the time sequence method is that the energy supply of the radio frequency tag is interrupted when the reader sends a pause, which must be compensated by loading a sufficiently large auxiliary capacitor or an auxiliary battery.
5, working frequency
The frequency that is usually used when the reader transmits is referred to as the operating frequency of the RFID system. The common operating frequencies are low frequency 125kHz, 134.2kHz and 13.56MHz. Low-frequency system generally refers to its operating frequency is less than 30MHz, the typical operating frequency: 125KHz, 225KHz, 13.56M, etc., these frequency applications of radio frequency identification systems generally have the corresponding international standards to support. Its basic characteristics are the low cost of electronic tags, the small amount of data stored in the tags, the short reading distance, and the various shapes of the electronic tags (card-shaped, loop-shaped, button-shaped, pen-shaped), and the reading antenna has poor directionality. Wait.
High-frequency system generally refers to its operating frequency is greater than 400MHz, the typical operating frequency band: 915MHz, 2.45GHz, 5.8GHz and so on. High frequency systems are also supported by numerous international standards in these frequency bands. The basic characteristics of the high-frequency system are the high cost of electronic tags and readers, the large amount of data stored in the tags, and the long distance to read (up to a few meters to ten meters). It is suitable for high-speed motion performance of objects, and its appearance is usually a card. The shape of the reading antenna and the electronic tag antenna have strong directionality.
6. System Advantages RFID is an easy-to-manage, simple and practical and flexible application technology that is especially suitable for automation control. It requires no manual intervention for identification work. It can support both read-only and read-write work modes. Contact or aiming; free to work in all kinds of harsh environments: short-range RF products are not afraid of oil, dust and other harsh environments, can replace bar codes, such as tracking the object in the factory's assembly line; long-range radio frequency products used for traffic , identification distance up to tens of meters, such as automatic charging or identification of vehicle identity. The radio frequency identification system mainly has the following system advantages:
Reading is quick and easy: The reading of the data does not require a light source, and can even be performed through the outer packaging. The effective identification distance is larger. When using the active label with its own battery, the effective identification distance can reach more than 30 meters;
Fast recognition speed: When the tag enters the magnetic field, the reader can instantly read the information, and can process multiple tags at the same time to realize batch identification;
Large data capacity: The two-dimensional barcode (PDF417) with the largest data capacity can only store up to 2725 digits; if it contains letters, the amount of storage will be less; RFID tags can be expanded to dozens of K according to the needs of users;
Long service life and wide range of applications: Its radio communication method can be applied to high-pollution and radioactive environments such as dust and oil, and its closed packaging greatly exceeds the printed bar code.
The tag data can be changed dynamically: the data can be written to by the programmer, thus giving the RFID tag the function of an interactive portable data file, and the writing time is less than the printed bar code;
Better security: not only can be embedded or attached to different shapes and types of products, but also can set password protection for reading and writing of tag data, thus having higher security;
Dynamic real-time communication: The tag communicates with the reader at a frequency of 50 to 100 times per second, so that as long as the RFID tag is attached to an object within the effective recognition range of the reader, it can dynamically track and monitor its position. .
1, a radio frequency identification system concept <br> <br> RFID system by a radio frequency automatic identification system tags, readers and computer networks thereof. Generally, the reader emits energy in an area to form an electromagnetic field. When the radio frequency tag detects the signal of the reader when passing through this area, the stored data is sent. The reader receives the signal sent by the radio frequency tag, and decodes and verifies the accuracy of the data. To achieve the purpose of identification.
2. Technology
Initially in the technical field, transponders are electronic modules that can transmit information to reply information. In recent years, due to the rapid development of radio frequency technology, transponders have new claims and meanings, and are also called smart labels or tags. The reader (reader) of the RFID electronic elevator certificate wirelessly communicates with the RFID electronic tag through the antenna, and can read or write the tag identification code and memory data. A typical reader includes a high-frequency module (transmitter and receiver), a control unit, and a reader antenna.
RFID radio frequency identification is a non-contact automatic identification technology. It automatically identifies target objects and obtains relevant data through radio frequency signals. The identification work can be performed in various harsh environments without manual intervention. RFID technology can identify high-speed moving objects and can identify multiple labels at the same time. The operation is quick and easy.
Tag: Composed of a coupling element and a chip, each tag has a unique electronic code and is attached to the object to identify the target object.
Reader: A device that reads (sometimes writes) tag information and can be designed as a handheld rfid reader (eg C5000W) or a stationary reader.
Antenna: Passes RF signals between tags and readers.
3, the working principle <br> <br> label into the magnetic field, receives radio frequency signals emitted by interpretation, transmits the product information stored in the chip (PassiveTag, a passive tag or a passive tag) is obtained by virtue of the induced current energy, Or the tag actively sends a signal of a certain frequency (ActiveTag, active tag or active tag). After the reader reads the information and decodes it, it sends it to the central information system for data processing.
A complete RFID system is composed of three parts: a reader and a tag (TAG), a so-called transponder, and an application software system. The working principle is that Reader emits a specific frequency. The radio wave energy is given to the Transponder to drive the Transponder circuit to send the internal data. At this point, the Reader receives the decoded data in sequence and sends it to the application program for processing.
The communication between the RFID card reader and the electronic tag and the energy sensing method can be roughly divided into two types: Inductive Coupling and Backscatter Coupling. Most low-frequency RFIDs generally use the first type, while higher frequencies mostly use the second type.
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 is usually composed of a coupling module, a transceiver module, a control module, and an interface unit. Half-duplex communication is generally used for information exchange between the reader and the transponder, and the reader is coupled to the passive transponder to provide energy and timing. In practical applications, management functions such as collection, processing, and remote transmission of object identification information may be further implemented through Ethernet or WLAN. The transponder is the information carrier of the RFID system. At present, transponders are mostly composed of coupled originals (coils, microstrip antennas, etc.) and microchips constituting a passive unit.
4, work methods
The basic working methods of radio frequency identification systems are divided into Full Duplex and Half Duplex systems and Sequence (SEQ) systems. Full duplex means that the RFID tag and the reader can transmit information to each other at the same time. Half-duplex indicates that the RFID tag and the reader can transmit information in both directions, but can only transmit information in one direction at the same time.
In full-duplex and half-duplex systems, the RF tag's response is transmitted in the presence of electromagnetic fields or electromagnetic waves emitted by the reader. Since the signal of the radio frequency tag is weak at the receiving antenna compared to the signal of the reader itself, an appropriate transmission method must be used in order to distinguish the signal of the radio frequency tag from the signal of the reader. In practice, data transmission from RFID tags to readers typically uses load reflection modulation techniques to load RF tag data onto the reflected echo (especially for passive RF tag systems).
In contrast to the timing method, the radiated electromagnetic field from the reader is periodically switched off. These intervals are identified by the RF tag and used for data transmission from the RF tag to the reader. In fact, this is a typical way of working with radar. The disadvantage of the time sequence method is that the energy supply of the radio frequency tag is interrupted when the reader sends a pause, which must be compensated by loading a sufficiently large auxiliary capacitor or an auxiliary battery.
5, working frequency
The frequency that is usually used when the reader transmits is referred to as the operating frequency of the RFID system. The common operating frequencies are low frequency 125kHz, 134.2kHz and 13.56MHz. Low-frequency system generally refers to its operating frequency is less than 30MHz, the typical operating frequency: 125KHz, 225KHz, 13.56M, etc., these frequency applications of radio frequency identification systems generally have the corresponding international standards to support. Its basic characteristics are the low cost of electronic tags, the small amount of data stored in the tags, the short reading distance, and the various shapes of the electronic tags (card-shaped, loop-shaped, button-shaped, pen-shaped), and the reading antenna has poor directionality. Wait.
High-frequency system generally refers to its operating frequency is greater than 400MHz, the typical operating frequency band: 915MHz, 2.45GHz, 5.8GHz and so on. High frequency systems are also supported by numerous international standards in these frequency bands. The basic characteristics of the high-frequency system are the high cost of electronic tags and readers, the large amount of data stored in the tags, and the long distance to read (up to a few meters to ten meters). It is suitable for high-speed motion performance of objects, and its appearance is usually a card. The shape of the reading antenna and the electronic tag antenna have strong directionality.
6. System Advantages RFID is an easy-to-manage, simple and practical and flexible application technology that is especially suitable for automation control. It requires no manual intervention for identification work. It can support both read-only and read-write work modes. Contact or aiming; free to work in all kinds of harsh environments: short-range RF products are not afraid of oil, dust and other harsh environments, can replace bar codes, such as tracking the object in the factory's assembly line; long-range radio frequency products used for traffic , identification distance up to tens of meters, such as automatic charging or identification of vehicle identity. The radio frequency identification system mainly has the following system advantages:
Reading is quick and easy: The reading of the data does not require a light source, and can even be performed through the outer packaging. The effective identification distance is larger. When using the active label with its own battery, the effective identification distance can reach more than 30 meters;
Fast recognition speed: When the tag enters the magnetic field, the reader can instantly read the information, and can process multiple tags at the same time to realize batch identification;
Large data capacity: The two-dimensional barcode (PDF417) with the largest data capacity can only store up to 2725 digits; if it contains letters, the amount of storage will be less; RFID tags can be expanded to dozens of K according to the needs of users;
Long service life and wide range of applications: Its radio communication method can be applied to high-pollution and radioactive environments such as dust and oil, and its closed packaging greatly exceeds the printed bar code.
The tag data can be changed dynamically: the data can be written to by the programmer, thus giving the RFID tag the function of an interactive portable data file, and the writing time is less than the printed bar code;
Better security: not only can be embedded or attached to different shapes and types of products, but also can set password protection for reading and writing of tag data, thus having higher security;
Dynamic real-time communication: The tag communicates with the reader at a frequency of 50 to 100 times per second, so that as long as the RFID tag is attached to an object within the effective recognition range of the reader, it can dynamically track and monitor its position. .
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