RFID tags are composed of tags, readers, and data transmission and processing systems. -Generally divided into active RFID, semi-active and passive RFID, the chip with antenna is stored in the chip, and the information that can identify the target is stored in the chip, and the main function is to identify the goods.

   So, how do RFID tags distinguish between active, semi-active and passive?

1. Different concepts
    Active RFID, also known as active RFID (Active tag), is usually used to track high-value items at a long distance. Compared with passive RFID, it can transmit a longer distance and can also adapt to more complex application environments.
    Semi-active RFID integrates the advantages of active RFID tags and passive RFID tags as a special marker. In most cases, it is often in a dormant state and does not work, and does not send an RFID signal to the outside world. Only when it enters the activation signal range of the low-frequency activator, the tag starts to work after it is activated.
    Passive RFID, that is, the passive radio frequency tag adopts the frequency hopping working mode and has anti-interference ability. Users can customize the standard data to read and write. The efficiency is faster in the special application system, and the reading distance can reach more than 10 meters.

Two, the working principle is different
    Active RFID tags means that the energy for the tag work is provided by the battery. The battery, memory and antenna together constitute an active electronic tag, which is different from the passive radio frequency activation method, which always sends information out of the set frequency band before the battery is replaced.
     Semi-active RFID, common active electronic tags work in the 433M frequency band or 2.4G frequency band, and work normally after being activated. The activation distance of the low-frequency activator is limited. It can only be accurately activated in a small distance and a small range. In this way, the low-frequency activator is used as the base point for positioning, and different base points are installed in different positions, and then used for a long distance in a large area The reader recognizes and reads the signal, and then uploads the signal to the management center in different uploading methods. In this way, the entire process of signal acquisition, transmission, processing, and application is completed.
     The performance of passive RFID tags is greatly affected by the tag size, modulation format, circuit Q value, device power consumption and modulation depth. The passive radio frequency tag has 1024bits memory capacity and ultra-wide working frequency band, which not only conforms to relevant industry regulations, but also enables flexible development applications.
It can read and write multiple tags at the same time. Passive radio frequency tag design, without battery, memory can be repeatedly erased and written more than 1000 times.

Three with or without built-in battery
     Active electronic tags support built-in batteries, passive radio frequency tags do not support built-in batteries, and special parts of half-source RFID tags rely on batteries to work.

Four, the price is different
      Active RFID: The price is high, and the battery life is relatively short;
      Passive RFID: The price is cheaper than active RFID, and the battery life is relatively long;
      Semi-source RFID: The price is relatively moderate, but the functions are relatively few.