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What is RFID? How RFID works? RFID Explained in Detail

RFID is the abbreviation of Radio Frequency Identification.

Its principle is the contactless data communication between the reader and the tag to achieve the purpose of identifying the target. RFID has a wide range of applications, typical applications include animal chip, car chip immobilizer, access control, parking control, production line automation, and material management.

What is RFID? How RFID works? RFID Explained in Detail


I Overview of RFID

II Working principle of RFID

III How RFID system is composed?

3.1 About the reader

3.2 About electronic tags

IV Features

4.1 Applicability

4.2 High efficiency

4.3 Uniqueness

4.4 Simplicity

I Overview of RFID

Radio frequency identification, or radio frequency identification technology, is a type of automatic identification technology that uses wireless radio frequency for non-contact two-way data communication. It uses radio frequency to read and write recording media (electronic tags or radio frequency cards) to achieve the purpose of identification 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 waves without contact with fast 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. In this way, the purpose of identification is achieved, and it can be used for data exchange, connecting an extremely complex system in series.

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 correspondingly divided into load modulation and backscatter modulation.


II Working principle of RFID

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, passive tag or passive tag). ), or the tag actively sends a signal of a certain frequency (Active Tag, active tag or active tag). After the reader reads and decodes the information, it is sent to the central information system for relevant data processing.

A complete RFID system is composed of three parts: a reader, an electronic tag, 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 drive the circuit to send out the internal data. At this time, the Reader receives the interpretation data in order and sends it to the application program for corresponding processing.

how RFID works

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 adopt a half-duplex communication mode for information exchange, and the reader provides energy and timing to the passive tag through 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.

III How RFID system is composed?

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

3.1 About the 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: transceiver antenna, frequency generator, phase-locked loop, 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.

3.2 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: 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.

RFID technology

IV Features

Generally speaking, the radio frequency identification technology has the following characteristics. 

4.1 Applicability

RFID technology relies on electromagnetic waves and does not require physical contact between the connecting parties. This makes it possible to establish connections without regard to dust, fog, plastic, paper, wood and various obstacles, and to complete communications directly.

4.2 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. 

4.3 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.

4.4 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.


1. What is RFID and how does it work?

RFID is a method of data collection that involves automatically identifying objects through low-power radio waves. Data is sent and received with a system consisting of RFID tags, an antenna, an RFID reader, and a transceiver.

2. What is RFID used for?

These radio waves transmit data from the tag to a reader, which then transmits the information to an RFID computer program. RFID tags are frequently used for merchandise, but they can also be used to track vehicles, pets, and even patients with Alzheimer's disease. An RFID tag may also be called an RFID chip.

3. Is RFID bad for health?

The shortest answer is No. Studies have shown that even the longest exposure to RFID tags does not have any negative consequences of health. This is true for even when subjects are wearing the tags on themselves. It is very safe when it comes to long term ad constant exposure.

4. What RFID means?

Radio Frequency Identification

Radio Frequency Identification (RFID) refers to a wireless system comprised of two components: tags and readers. The reader is a device that has one or more antennas that emit radio waves and receive signals back from the RFID tag.

5. Is RFID tag and FASTag same?

FASTag is a device that employs Radio Frequency Identification (RFID) technology for making toll payments directly while the vehicle is in motion. FASTag (RFID Tag) is affixed on the windscreen of the vehicle and enables a customer to make the toll payments directly from the account which is linked to FASTag.

6. What is RFID and its advantages?

RFID technology automates data collection and vastly reduces human effort and error. RFID supports tag reading with no line-of-sight or item-by-item scans required. RFID readers can read multiple RFID tags simultaneously, offering increases in efficiency.