What is RFID?

RFID is an acronym for “radio-frequency identification” and refers to a technology whereby digital data encoded in RFID tags or smart labels are captured by a reader via radio waves. RFID is similar to barcoding in that data from a tag or label are captured by a device that stores the data in a database. RFID, however, has several advantages over systems that use barcode asset tracking software. The most notable is that RFID tag data can be read outside the line-of-sight, whereas barcodes must be aligned with an optical scanner.

RFID Overview

The wireless radio frequency recognition namely the radio frequency recognition technology (Radio Frequency Identification, RFID), is the automatic diagnosis technology one kind, carries on the non-contact two-way data communication through the wireless radio frequency way, uses the wireless radio frequency way to record media (electronic label or the radio frequency card) to read and write, thus achieves the recognition target and the data exchange purpose, it is considered to be one of the most development potential information technology in the 21st century.

The wireless radio frequency recognition technology through the radio wave does not contact the rapid information exchange and the storage technology, through the wireless communication combines the data access technology, then connects the database system, to realize the non-contact two-way communication, thus achieves the recognition purpose, is used for the data exchange, the series links up an extremely complicated system. In the recognition system, through the electromagnetic wave realization electronic label read-write and the communication. According to the communication distance, may divide into the near field and the far-field, for this reason reads/writes the equipment and the electronic label between the data exchange method also correspondingly is divided into the load modulation and the backscatter modulation.

RFID Development Process

  • 1940-1950: Due to the development and progress of radar technology and thus derived from RFID technology, the theoretical basis of RFID was born in 1948.
  • 1950-1960: people began to explore RFID technology, but did not move away from laboratory research.
  • 1960-1970: Theories were developed and the system began to be used in practice.
  • 1970-1980: RFID technology was constantly updated, product research was gradually deepened, and testing of RFID began to accelerate further. And the application of related systems was realized.
  • 1980-1990: RFID technology and related products were developed and applied in the market, and a variety of fields of use emerged.
  • 1990-2000: People began to pay attention to the standardization of RFID, and RFID systems were seen in many areas of life.
  • After 2000: People generally recognize the importance of standardization issues, RFID products are further enriched and developed, whether active, passive or semi-active electronic tags are beginning to develop, related production costs are further reduced, and application fields are gradually increasing.
  • Today, the technical theory of RFID has been further enriched and developed, people develop single-chip electronic tags, multi-electronic tag reading, wireless readable and writable, adaptable to high-speed moving objects RFID technology continues to develop, and related products have come into our lives and began to be widely used.

How Does RFID Work?

Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver, and a transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an identifying inventory number, back to the reader. This number can be used to track inventory goods.

Passive tags are powered by energy from the RFID reader’s interrogating radio waves. Active tags are powered by a battery and thus can be read at a greater range from the RFID reader, up to hundreds of meters.

Unlike a barcode, the tag does not need to be within the line of sight of the reader, so it may be embedded in the tracked object. RFID is one method of automatic identification and data capture (AIDC).

RFID tags are used in many industries. For example, an RFID tag attached to an automobile during production can be used to track its progress through the assembly line, RFID-tagged pharmaceuticals can be tracked through warehouses, and implanting RFID microchips in livestock and pets enables positive identification of animals. Tags can also be used in shops to expedite checkout, and to prevent theft by customers and employees.

Since RFID tags can be attached to physical money, clothing, and possessions, or implanted in animals and people, the possibility of reading personally linked information without consent has raised serious privacy concerns. These concerns resulted in standard specifications development addressing privacy and security issues.

RFID Components

1. About the Reader

A reader is a device that reads out the information from a tag or writes the information that the tag needs to store to the tag. Depending on the structure and technology used, the reader can be a read/write device and is the information control and processing center of the RFID system. In RFID system operation, an electromagnetic field is formed by the reader sending RF energy in a region, the size of which depends on the transmitting power. The tag in the reader coverage area is triggered to send the data stored in it, or modify the data stored in it according to the reader’s instructions, and can communicate with the computer network through the interface. The basic components of a reader usually include transceiver antenna, frequency generator, phase-locked loop, modulation circuit, microprocessor, memory, demodulation circuit, and peripheral interface.

  1. Transceiver antenna: send RF signal 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: generates the required carrier signal.
  4. Modulation circuit: loads the signal sent to the tag into the carrier and sends it out by the RF circuit.
  5. Microprocessor: generates the signal to be sent to the tag, and at the same time decodes the signal returned by the tag, and returns the decoded data to the application, and in the case of encrypted systems also requires decryption operations.
  6. Memory: store user programs and data.
  7. Demodulation circuit: demodulates the signal returned by the tag and hands it to the microprocessor for processing.
  8. Peripheral interface: communicates with the computer.

2. About Electronic Tags

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

  1. Transceiver antenna: receives the signal from the reader and sends the requested data back to the reader.
  2. AC/DC circuit: Uses the electromagnetic field energy emitted by the reader and provides a stable power supply for other circuits through the output of the voltage regulator circuit.
  3. Demodulation circuit: removes the carrier wave from the received signal and demodulates the original signal.
  4. Logic control circuit: decodes the signal from the reader and sends back the signal according to the reader’s requirements.
  5. Memory: As the 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 to send to the reader after the modulation circuit.

RFID Classification

Radiofrequency identification technology can be divided into three categories according to its tag power supply method, namely passive RFID, active RFID, and semi-active RFID.

Passive RFID

In the three types of RFID products, passive RFID appears at the earliest time, the most mature, its application is also the most extensive. In passive RFID, electronic tags by accepting radio frequency identification reader transmission to the microwave signal, as well as through the electromagnetic induction coil to obtain energy to their own brief power supply, so as to complete this information exchange. Because the power supply system is omitted, so the volume of passive RFID products can reach the centimeter scale or even smaller, and their own structure is simple, low cost, low failure rate, and long service life. But as a price, passive RFID’s effective recognition distance is usually shorter, generally used for close contact identification. 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.

Active RFID

Active RFID emerged not long ago but has been in various fields, especially on the highway electronic non-stop toll collection system plays an indispensable role. Active RFID through the external power supply, active to send signals to the radio frequency identification reader. Its volume is relatively large. But also, therefore, has a long transmission distance and high transmission speed. A typical active RFID tag can establish contact with the RFID reader from a hundred meters away, and the reading rate can reach 1,700read/sec. Active RFID mainly works in 900MHz, 2.45GHz, 5.8GHz, and other higher frequency bands, and has the function that can identify multiple tags at the same time. Active RFID’s long-range and high efficiency make it essential in some RFID applications that require high performance and a large range.

Semi-active RFID

Passive RFID does not power itself, but the effective recognition distance is too short. Active RFID recognition distance is long enough, but need an external power supply, the volume is larger. And 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, only the tag to maintain data in the part of the power supply, so power consumption is small, can be maintained for a long time. When the tag enters the RFID reader recognition range, the reader first now with 125KHz low-frequency signal in a small range of precise activation of the tag to make it enter the working state and then through the 2.4GHz microwave and its information transmission. That is to say, the first use of low frequency signal precise positioning, and then use high-frequency signal fast transmission data. The usual application scenario is that multiple low-frequency readers are placed at different locations for activating semi-active RFID products in a wide range that can be covered by a high-frequency signal. This accomplishes both positioning and information collection and transmission.

RFID Features

  1. Applicability: RFID technology relies on electromagnetic waves and does not require physical contact between the connecting parties. This makes it possible to establish connections regardless of dust, fog, plastic, paper, wood, and various obstacles, and to complete communications directly.
  2. High efficiency: RFID system read and write speed is extremely fast, a typical RFID transmission process is usually less than 100 milliseconds. RFID readers in the high frequency band can even identify and read the contents of multiple tags simultaneously, greatly improving the efficiency of information transmission.
  3. Uniqueness: each RFID tag is unique, through the RFID tag and product one-to-one correspondence, you can clearly track the subsequent circulation of each product.
  4. Simplicity: RFID tag structure is simple, high recognition rate, the required reading equipment is simple. Especially with the gradual popularization of NFC technology on smart phones, each user’s cell phone will become the simplest RFID reader.


In terms of its external manifestation, the carrier of the radio frequency identification technology is generally to have the characteristics of waterproof, anti-magnetic, high-temperature resistance, etc., to ensure that the radio frequency identification technology has stability when it is applied. In terms of its use, radio frequency identification has advantages in real-time update data, storage information volume, service life, work efficiency, security, and so on. Radiofrequency identification can reduce the human material and financial resources under the premise, more convenient update the existing information, make the work more convenient; radio frequency identification technology based on the computer and so on to store information, the maximum can reach several megabytes, can store the information volume is large, guarantee the smooth progress of work; radio frequency identification technology has a long service life, as long as the staff pays attention to the protection when using, it can carry on the repeated use; radio frequency identification technology has changed the former to the information processing inconvenience, realized the multi-target simultaneously to be recognized, greatly improved the working efficiency; And the radio frequency recognition at the same time has the password protection, is not easy to be forged, the security is high. The technology similar to radio frequency identification technology is the traditional bar code technology. The traditional bar code technology is worse than radio frequency identification technology in updating data, storing information quantity, service life, working efficiency, security, etc. It can’t adapt well to the demand of our country’s current social development, and it is also difficult to meet the needs of industry and related fields.

RFID Applications

1. Logistics

Logistics and warehousing are one of the most promising application areas of RFID, UPS, DHL, FedEx, and other international logistics giants are actively experimenting with RFID technology, with a view to large-scale applications in the future to enhance its logistics capabilities. Processes that can be applied include the logistics process of goods tracking, automatic information collection, warehouse management applications, port applications, postal parcels, express delivery, etc.

2. Transportation

Cab management, bus hub management, railroad locomotive identification, etc., there have been many more successful cases.

3. Identification

RFID technology is widely used in personal identification documents because it has fast reading and is difficult to forge. Such as the development of the electronic passport project, our country’s second-generation ID card, student ID card, and other various electronic documents.

4. Anti-counterfeiting

RFID has the characteristic of being difficult to forge, but how it is applied to anti-counterfeiting still needs active promotion by the government and enterprises. Possible areas of application include anti-counterfeiting of valuable items (cigarettes, wine, drugs) and anti-counterfeiting of tickets, etc.

5. Asset management

It can be applied to the management of all kinds of assets, including valuable items, items with high similarity in quantity or dangerous goods, etc. With the reduction of tag price, RFID can manage almost all items.

6. Food

It can be applied to the management of fruits, vegetables, fresh and food products. Applications in this field require innovation in the design of tags and application models.

7. Information statistics

With the use of radio frequency identification technology, information statistics becomes simple and fast work. By the query software of the archives information management platform transmits the statistical inventory signal, the reader quickly reads the data information and relevant storage information of the archives in the collection, and intelligently returns the acquired information and the information in the central information repository for proofreading. If for the archives that cannot be matched, the manager uses the reader to start on-site verification, adjust the system information and on-site information, and then complete the information statistics.

8. Access Application

When inquiring about archival information, the archives manager finds out the file number with the help of the inquiry management platform, and the system reads the data and information in the central information database according to the file number, and after verification, transmits the signal for the file to leave the storage, and the intelligent identification function module of the storage space management platform will combine the file number with the relevant storage space number to find out the specific part where the file is kept. After the manager passes out the file-out signal, the indicator light on the storage place point lights up immediately. When the information leaves the storage, the radio frequency identification reader will feedback the acquired information to the management platform, and the manager will verify again and leave the storage after verifying the same for the outgoing file and the file checked. And, the system will record the information out of the warehouse time. If the feedback file and the checked file do not match, the alarm module within the security management platform will transmit an abnormal warning.

9. Security control

The security control system can realize functions such as time monitoring and abnormal alarms for archives to avoid destruction and theft of archives. When archives are returned on loan, especially physical archives, which are often used for exhibitions, evaluation checks, etc., managers carefully check the returned archives and verify them with the information before they were loaned out, so that they can find out in time whether the archives are damaged, missing, etc.

In this video, RFID (Radio Frequency Identification) Technology has been explained. So, in this video, what is RFID, what is inside this RFID system, how RFID works, and the application of RFID have been explained.


  1. What is RFID and How Does RFID Work?
  2. Radio-frequency identification