Three Minutes to Take You to Understand RFID Technology

RFID technology actually refers to radio frequency technology. Its technology mainly relies on the principle of magnetic field or electromagnetic field to realize two-way communication between devices through radio frequency, so as to realize the function of exchanging data. The biggest feature of this technology is that it can obtain each other without contact. RFID information, ETC, logistics, and libraries are several typical application scenarios. The commonly used radio wave frequency bands for RFID technology mainly include: low frequency, high frequency, ultra-high frequency and microwave frequency bands.RFID system compositionRFID system is mainly composed of three parts: reader, electronic label and data management system.

RFID Reader: Also known as a reader , it is mainly used to read out the information in the electronic tag, or write the information required by the tag into the tag. According to different uses, readers are divided into read-only readers and read/write readers, which are the information control and processing center of the RFID system. When the RFID system works, the reader transmits radio frequency energy in an area to form an electromagnetic field, and the size of the area depends on the transmission power. The tags in the coverage area of the reader are triggered, 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 .

RFID Tag: The electronic tag is mainly used to store certain data information. At the same time, it will accept the signal from the reader and send the required data back to the reader. The electronic tag is generally attached or fixed to the on the item.

Data management system: The main work is to process the electronic tag data transmitted by the reader for analysis, and at the same time complete the functions required by the user. For example, the following system flow:

How RFID systems work

When the rfid tag is within the recognition range of the reader, the reader emits radio wave energy of a specific frequency, and the electronic tag will receive the radio frequency signal sent by the reader and generate an induced current. Using the energy generated by this current, the electronic tag sends out the information stored in its chip. Such electronic tags are generally referred to as passive tags or passive tags, or the tags actively send a signal of a certain frequency to the reader, and such electronic tags are generally referred to as active tags or active tags. After the reader receives the information returned by the electronic tag, it decodes it, and then sends it to the relevant application software or data management system for data processing.

RFID classification

RFID technology can be divided into three categories according to the power supply method of its tags, namely passive RFID, active RFID and semi-active RFID.

1. Passive RFID

The passive RFID system obtains energy through the electromagnetic induction coil to supply power to itself for a short time and completes the exchange of information. The utility model has the advantages of simple structure, low cost, low failure rate and long service life. However, the effective identification distance of passive RFID is usually short, and it is generally used for close contact identification. Passive RFID mainly works in the lower frequency band 125kHz, 13.56MHz and so on. Typical applications of passive RFID systems include: bus cards, second-generation ID cards , and canteen meal cards.

2. Active RFID

The research and development of active RFID system started late, but it has been applied in various fields. ETC, for example, uses an active RFID system. Active RFID is powered by an external power supply or built-in battery, and actively sends signals to the reader, which has a longer transmission distance and faster transmission speed. Active RFID tags can establish data communication with readers within a range of 100m, and the reading rate can reach 1700 times/s. Active RFID mainly works in ultra-high frequency bands and microwave frequency bands such as 90OMHz, 2.45GHz, 5.8GHz, and has the function of identifying multiple tags at the same time. The above-mentioned characteristics of active RFID systems make them widely used in high-performance, large-scale RFID scenarios.

3. Semi-active RFID

Because the effective identification distance of passive RFID system is short; active RFID identification distance is long enough, but it needs external power supply or built-in battery, and the volume is large. In order to solve this contradiction, the semi-active RFID system came into being. Semi-active RFID technology is also known as low frequency activation trigger technology. Under normal circumstances, semi-active RFID tags are in a dormant state and only supply power to the part of the tag that holds data, so the power consumption is small and can be maintained for a long time. When the tag enters the identification range of the RFID reader, the reader first accurately activates the tag in a small range with a low-frequency signal of 125kHz to make it work, and then transmits information to it through 2.4GHz microwave. That is to say, multiple low-frequency readers are placed in different positions for activating semi-active RFID products, so that both positioning and data collection and transmission can be realized.

To achieve RFID asset management, you can consider using NB-IOT or Lora technology to transmit the data collected by the RFID reader to the Lora base station in real time, and upload it to the backend. At present, it is understood that some companies are already trying, RFID is used for identification, and NB or Lora is used for transmission. If you develop it yourself, you need to do hardware docking and data docking, and then do the backend. There should be mature hardware solutions on the market, but the software backend must be developed by yourself. Generally, hardware companies will provide SDKs. At present, RFID is widely used, involving all aspects of social life. It can be applied in logistics, retail, manufacturing, clothing industry, medical treatment, identity recognition, anti-counterfeiting, asset management, transportation, food, automobile, military, financial payment and other fields. PFID technology It should be a very promising development direction.