The most complete introduction to the overall RFID technology

Radio Frequency IDentification (RFID). An RFID system is a set of hardware devices based on RFID technology that has a wealth of industrial applications.

The RFID system consists of three main components:

2.1 RFID tags (Tag)

also known as smart tags, are divided into active tags and passive tags. Active tags come with an independent power supply system and can actively send signals; while passive tags have no power supply and require energy from the reader to send signals. The tag contains an electronic memory chip for storing information.

2.2 RFID Readers (Readers):

are used to transmit signals to activate tags and read or write the data inside the tags. Depending on the application, the reader can be either fixed or handheld.

2.3 Backend database (Database)

Stored data read by the RFID system, and interact with it to manage and process the data to achieve more complex data analysis and applications. General routine for the PC, there are some embedded systems.

2.4 Working Principle

1.Activation: The reader sends a radio wave signal to the tag to activate it.
2.Data transmission: Once activated, the tag sends the information stored on the chip to the reader via radio waves.
3.Data Processing: The reader receives the information and transmits it to the backend system for further processing and analysis.
Overall see figure, RFID reader produces high-frequency small signal, using the characteristics of the electromagnetic field through the antenna to send signals to RFID tags, communication data for labeling operations, and then the tag produces an inductive current in the electromagnetic field back to the RFID reader!

2.5 categorization

Classification based on operating frequency

RFID technology has been divided into three categories: 1. Low-frequency (LF) RFID 30KHz – 300KHz, reading distance is less than 10cm, low data transmission rate is not susceptible to other electromagnetic interference, can be used in the water or near the metal was often used in the production of access control cards, livestock tracking 2. High-frequency (HF) RFID 3MHz – 30MHz, reading distance between 10cm and 1m, high data transmission rate, susceptible to other electromagnetic interference, not suitable for use near water or metal, often used for non-contact payment and other data transmission of a large amount of the scene 3. Ultra-high-frequency (UHF) RFID 300MHz – 3GHz, read UHF RFID 300MHz – 3GHz, reading distance up to 12m, fastest data transmission rate Most susceptible to electromagnetic interference, but due to the strong investment of major manufacturers, a variety of anti-jamming design far more than the LF and HF RFID Today, as the optimal choice among the three technologies, is used by manufacturers for a variety of purposes.

RFID frequency band

2.6 High Frequency RFID

Advantages

•  Higher data transfer rate: Compared to low frequency RFID, high frequency RFID has a higher data transfer rate, enabling faster reading and writing of tag data.
•  shorter read range: HF RFID usually has a shorter read range, which helps to minimize interference and improve data security. 3. better immunity to interference.
• better anti-jamming ability: due to the higher operating frequency, high-frequency RFID is less susceptible to electromagnetic interference and metal reflections, making it suitable for applications in certain complex environments.
• Wider application support: HF RFID technology is widely supported in many application scenarios, such as access control systems, library management, and transportation ticketing.

Disadvantages:

• Interference by metals and liquids: The read performance of HF RFID in contact with metals or liquids may be affected, which limits its application in certain environments.
• Shorter reading distance: Compared to UHF RFID, HF RFID has a shorter reading distance, which may limit some application scenarios that require a longer identification distance.

2.7 Low Frequency RFID (LF)

Advantages

• Better penetrability: LF RFID has better penetrability and relatively less interference with metals and liquids, so it performs more reliably in some specific environments.
• Longer reading distance: Compared with high-frequency RFID, low-frequency RFID usually has a longer reading distance, which makes it suitable for some application scenarios that require long-distance identification.
• Wider standardization: Low-frequency RFID technology has been widely standardized and applied in many countries, so it has higher compatibility and stability worldwide.

Disadvantages:

•  lower data transfer rate: low-frequency RFID has a relatively low data transfer rate, so it may be less suitable for applications that deal with large amounts of data or require fast reads.
• Susceptibility to interference: Due to the lower operating frequency, low-frequency RFID may be more susceptible to external interference in certain environments, which may affect its performance and stability.

2.8 Classification based on whether the electronic tag is powered or not

• Active RFID system RFID tags have their own power supply device. Active UFH RFID tag broadcast distance can reach up to 100m, commonly used in tracking large equipment or vehicles Active RFID tags are subdivided into two types Interrogation RFID tags: tags only receive electromagnetic signals from the read-write will be energized to broadcast signals, more power-saving, but need to be triggered by a closer distance Beacon RFID tags: tags will be energized to broadcast signals at regular intervals (the time can be set in advance), more power consumption, but can be used for real-time location. Beacon RFID tags: tags will be energized at regular intervals to broadcast signals (time interval can be set in advance), more power consumption, but can be used for real-time positioning
•  passive RFID system RFID tags do not have their own power supply. When the reader sends out electromagnetic waves, RFID tags based on the received electromagnetic waves to charge and send out signals or modify the stored data to achieve information transmission can be realized in LF, HF, UHF RFID technology, the distance is generally less than 10m Compared to the active system cost is lower, easier to manufacture. At the same time, because the tag does not have a power supply, so it is often used in book tags, access cards or embedded in electronic devices, once installed can be used for a long time without maintenance.

3. RFID Internal Components

3.1 Electronic Tags

RFID Tag Information Storage An RFID tag consists of a chip and an antenna. The antenna is used to transmit data, which is stored in the chip. Chip contains EEPROM (electronic erase reproducible read-only memory) can be in the absence of power supply in the case of long-term storage of data in the supply of a specific voltage, you can write or modify the data Read-only RFID tags: factory written data, and will not be modified thereafter, support for wireless read data Wired read/write RFID tags: can be plugged into the power supply cable to modify the data, support for wireless read data Wireless read/write RFID tags: can read data wirelessly and write data wirelessly.

3.2 Passive RFID tag power supply principle In a word

Electromagnetic induction – the electromagnetic wave emitted by the reader generates an induced current in the tag’s coil to supply power.

3.3 Read-write device

Fixed readers: several parts of the device can create a tightly controlled “interrogation area”, labels in and out of the interrogation area can be read in this clearly defined reader area. Mobile readers: can be used handheld or mounted on the vehicle to use.

3.4 software system

Not fixed, individually customized for each manufacturer.

3.5 Electronic Labeling Explained

UHF RFID tag basic composition of the three elements of the most important is the chip, which determines the function of the label and the main performance, the same chip is also the most complex design of the most technically difficult part.

4. Label Hardware Components

RFID tags are formed by the inlay plus surface materials, and then as long as the three parts, the chip, antenna, and attached to the substrate composition, the substrate is generally a standard pcb or soft and transparent PER polyester film substrate The technology used is the leakage of the board printing technology.

Tag chip is mainly composed of three parts: digital part, analog part and storage part, as shown in Figure 4-28. The role of the digital part of the protocol processing, logic processing, global arithmetic control processing, etc., Chapter 3, all the contents of the protocol-related functions are handled by the digital part. Analog part of the role is: power management, modulation and demodulation, master frequency clock, which power management part of the received RF electromagnetic wave rectified into DC power to the entire tag chip power supply, master frequency clock for the digital part and the storage part of the system to provide shock clock, modulation and demodulation to complete the tag and reader communication signal processing work. Storage part of the EPC, TID, User and other areas of the storage area, now the commonly used memory for the NVM (non-volatile memory) or EEPROM, general storage size of several hundred bits.

Through the following tag structure block diagram, you can more clearly understand the relationship between the three parts. The leftmost is the analog RF interface part (Analog RF interface), the antenna is connected to the analog part, which has four main devices: Rectifier (Rectifier), plays the role of the front-end rectifier; reference voltage generation (Vreg), to provide a stable voltage for the whole system; Demodulator (Demodulator); Modulator (Modulator). Modulator). The middle part is the digital control part (Digital Control), which functions as anti-collision algorithm (Anti-collision); read-write operation (Read Write Control); access control (Access Control); RF interface control (RF Interface Control), the digital part and the analog part of the data communication, and control the digital part and the analog part of the data communication. analog part for data communication and to control the read and write operation of the storage part. On the far right is the EEPROM memory (storage section), which has an internal charge pump boost circuit (Charge Pump) to provide a high voltage when writing labels.

4.1 Label Data Format Internal Partitioning

UHF RFID tag chip needs to comply with the EPC C1Gen2 standard (referred to as Gen2 protocol), that is to say, all UHF RFID tag chip internal storage structure is roughly the same. As shown in the figure, the tag chip storage area is divided into four areas (Bank) are Bank 0 reserved area (Reserved), Bank 1 electronic code area (EPC), Bank 2 manufacturer code area (TID), Bank 3 user area (User).

•  Reserved area: Kill Password and Access Password.

• EPC area: storage EPC number and so on.

• TID area: storage label identification number, each TID number should be unique.

• User area: store user-defined data. In addition there are various blocks of Lock status bit used is also the nature of the storage unit.

Different manufacturers of electronic tags, the use of storage media, the size of the data area and the interface are different.

Which Bank 0 reserved area is also known as the password area, there are two groups of 32-bit password, respectively, access password  and inactivation password , inactivation password is commonly known as the kill password. When the lock command is used, the access password is needed to read and write some areas of the chip. When the chip needs to be killed, the chip can be completely killed by the Kill Password.

Bank 1 is the electronic code area, which is the most familiar EPC area. According to Gen2 protocol, the first information to get the label is the EPC information, and only after that can you access the other storage area for access.EPC area is divided into three parts:

CRC16 checksum section totaling 16 bits, communication is responsible for checking whether the EPC obtained by the reader is correct.

PC part (Protocol Control) a total of 16 bits, control the length of the EPC, its first 5 bits of the binary number multiplied by 16 for the length of the EPC, such as 96 bits of EPC when the PC = 3000, its first 5 bits for 00110, corresponding to the decimal for the 6, multiplied by 16 for the 96Bit. according to the protocol requirements, the PC can be equal to 0000 to F100. Equivalent to the length of the EPC is 0, 32 bits, 64 bits until 496 bits. But in general, UHF RFID applications in the length of the EPC in the 64 bits to 496 bits between, that is, the PC value of 2800 to F100 between. In the usual application of the role of PC in the EPC often people can not figure out, will be stuck in the EPC length of the setup and thus bring a lot of trouble.

The EPC portion, which is what the end user gets from the application layer for the chip’s electronic code.

Bank 2 is the vendor coding area, where each chip has its own unique code.

Bank 3 for the user storage area, the storage area according to the protocol stipulates that the minimum space is 0, but most of the chip in order to facilitate customer applications, increase the user storage space, the most common storage space for 128 bits or 512 bits.

After understanding the storage area of the label, you need to further understand the Gen2 several operating commands that read , write, lock , kill .Gen2 commands are very simple, the operating commands are only four, and the label’s storage area status is only two kinds of: locked, unlocked.

Because the read and write commands are related to whether the data area is locked, we start with the lock command. Lock command on the four storage areas have a total of four decomposition commands are locked, unlocked , permanently locked , permanently unlocked , as long as the access code is not all 0 can be locked command. The operations corresponding to the four zones are shown in the table below.

4.2 Read and write locked operation

The read command, as the name implies, reads the data in the storage area. If the storage area is locked, you can access the data area through the Access command as well as the access password, and the specific read operation is shown in the following table.

Write command, similar to the read command, if the storage area is not locked, you can operate directly, if the storage area has been locked need to access the data area through the Access command and the access password to access the specific read operations as shown in the table below.

The kill command is an end-of-life command, once a chip is killed it can never be brought back to life, unlike the lock command which can be unlocked. As long as the reserved area is locked and the kill code is not all 0, the kill command can be activated. In general, the kill command is seldom used, and the chip will only be killed in some confidential or privacy-related applications. If you want to get the TID number of the chip after the chip has been killed, you can only do it by dissecting the chip, which costs a lot, so don’t try to start the kill command in normal applications. Similarly in the project you have to prevent people from messing with it, the best way is to lock the reservation and protect the access password.

5. RFID Applications

5.1 ETC

ETC (ElectronicTollCollection abbreviation) that is, electronic non-stop toll collection system. Refers to the vehicle through the toll booths, the use of RFID technology on board equipment for vehicle identification, information writing (entrance) and automatically from the pre-bound IC card or bank account to deduct the corresponding funds (export), is the international efforts to develop and promote the popularization of a road, bridges, tunnels and car parks for the management of the electronic toll collection system. ETC system mainly consists of automatic vehicle identification system, center management system and other auxiliary facilities. Among them, the vehicle automatic identification system consists of OBU (On board unit, vehicle unit), RSU (Road side unit, roadside unit), loop sensor and so on.

OBU (i.e. electronic tag) stores the relevant information of the vehicle and is generally installed on the front windshield of the vehicle.RSU (i.e. intelligent traffic charging RFID read-write) is installed next to the toll station. Loop sensors are installed underneath the lane floor. The center management system stores a large amount of information about registered vehicles and their owners. When the vehicles passes the toll station mouth, the loop road inductor senses the vehicles, the intelligent traffic charges the RFID read-write to send out the inquiry signal, the RFID electronic label makes the response, and carries on the two-way communication and the data exchange, the center management system obtains the vehicles to recognize the information to carry on the comparison judgement, according to the different situation to control the management system to produce the different operation, thus realizes to the traveling vehicles the automatic management.

5.2 library

Libraries have used RFID to replace bar codes on library materials. The tags can contain identifying information or can simply be keys in a database.An RFID system can replace or supplement bar codes and may provide another method of inventory management and patron self-checkout. It can also act as a security device, replacing more traditional electromagnetic security bars.

It is estimated that more than 30 million library collections worldwide now contain RFID tags, including some in the Vatican Library in Rome.

Because RFID tags can read items, they can scan items without having to open a book cover or DVD case, and can read a stack of books at the same time. Book tags can be read as the books move along the conveyor belt, reducing staff time. This can all be done by the borrower themselves, reducing the need for library staff assistance. Using portable readers, an entire shelf of materials can be inventoried in a matter of seconds. [95] However, as of 2008, this technology is still too expensive for many small libraries, with the conversion period for the average-sized library estimated at 11 months.A 2004 Dutch estimate was that a library lending 100,000 books per year should plan to spend 50,000 euros (checkout and return stations: 12,500 each, detection porches each 10,000; 0.36 per tag).RFID reduces the burden on staff and may also mean that fewer staff are needed.Library staffing budgets are decreasing and infrastructure budgets are increasing, making it necessary for libraries to increase automation to compensate for the reduction in the size of their staff.

Privacy issues are raised around the use of RFID in libraries. Since some RFID tags can be read from up to 100 meters (330 feet) away, there are concerns about whether sensitive information can be collected from unwanted sources. However, library RFID tags do not contain any patron information, and most tags used in libraries use frequencies that can only be read from about 10 feet (3.0 meters). Another concern is that non-library organizations may be able to record the RFID tags of everyone who leaves the library without the librarian’s knowledge or consent. A simple option is to have books transmit a code that only makes sense in conjunction with the library’s database. Another possible enhancement is to provide a new code for each book each time it is returned.

5.3 Shopping malls (merchandise labeling)

In general, the big shopping malls many clothes tag inside the RFID tag, of course, there are similar to Uniqlo like black and white plastic shells wrapped inside the dye and RFID tags, normal payment will be removed, otherwise ensure that the clothes go out through the RFID door gates to be able to send an alarm, forced removal will be the clothes stained.

RFID is used for item-level tagging in retail stores. In addition to inventory control, it prevents customer (shoplifting) and employee (“shrink”) theft through the use of Electronic Article Surveillance (EAS) and provides customers with a self-checkout process. Different types of tags can be physically removed using special tools or electronically deactivated after paying for an item. When leaving the store, customers must pass near an RFID detector; if they have an item with an active RFID tag, an alert will sound, both indicating the unpaid item and identifying what it is.

5.4 Medical field

The adoption of RFID in the healthcare industry has been widespread and very effective. Hospitals were among the first users to combine active and passive RFID. Active tags track high-value or frequently moving items, and passive tags track smaller, lower-cost items that only require room-level identification. Healthcare facility rooms can collect data from the transmission of RFID badges worn by patients and staff, as well as tags assigned to items such as mobile medical equipment. The U.S. Department of Veterans Affairs (VA) recently announced plans to deploy RFID in hospitals across the U.S. to improve care and reduce costs.

Since 2004, many U.S. hospitals have been implanting RFID tags in patients and using RFID systems, often for workflow and inventory management. The use of RFID to prevent confusion between sperm and eggs is also being considered in IVF clinics.

In October 2004, the FDA approved the first RFID chip in the U.S. that can be implanted in the human body. According to the company, VeriChip’s 134 kHz RFID chip, which integrates personal medical information, could save lives and limit the harm caused by medical errors. Anti-RFID activists Katherine Albrecht and Liz McIntyre discovered an FDA warning letter detailing health risks. According to the FDA, these include “adverse tissue reactions,” “migration of the implantable transponder,” “implantable transponder malfunction,” “electrical hazards,” and “risk of injury or death. electrical hazards” and ‘magnetic resonance imaging [MRI] incompatibility’.

In the field of ophthalmology, such as the da Vinci femtosecond treatment system, RFID tags are generally added to some of the disposable consumables to ensure that the consumables will not be reused, but also to ensure that the consumables have a certain degree of specificity, so that purchasers can not arbitrarily change the brand of the consumables, thus enabling the manufacturers to obtain higher profits.

Some relevant notes

6. NFC and RFID Relationship

NFC can be regarded as a subset of RFID, 13.56MHZ is the working frequency band of NFC, NFC promotion is mainly due to the fact that the enterprise has formulated the communication protocol and working mode earlier.

7.Conclusion

RFID (Radio Frequency Identification) technology represents a transformative advancement in the way we track, identify, and manage objects, assets, and data across various industries. From its fundamental components—tags, readers, and antennas—to its diverse applications in supply chain management, retail, healthcare, and beyond, RFID offers unparalleled efficiency, accuracy, and automation. This comprehensive introduction highlights the versatility of RFID, its ability to operate in different frequency ranges, and its integration with emerging technologies like IoT and AI, which further enhance its capabilities. While challenges such as cost, privacy concerns, and technical limitations exist, the continuous evolution of RFID technology promises even greater innovation and adoption in the future. As businesses and industries increasingly embrace RFID, it is clear that this technology will remain a cornerstone of modern automation and data-driven decision-making.

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