RFID radio frequency identification is a non-contact automatic identification technology that can automatically identify target objects and obtain relevant data through radio frequency signals. The recognition work does not require manual intervention, and can work in various harsh environments. RFID technology can identify high-speed moving objects, and can identify multiple electronic tags at the same time, the operation is quick and convenient, and is often used in supermarkets.
RFID Tag (Rfid Tag): Composed of coupling elements and chips, each RFID tag has a unique electronic code, attached to the object to identify the target object, usually called an electronic tag or smart tag RFID electronic tags: active tags, passive tags, semi-active and semi-passive tags. The working principle of RFID: After the tag enters the magnetic field, it receives the radio frequency signal from the reader, and uses the energy obtained by the induced current to send the product information stored in the chip (passive tag, passive tag or passive tag), or take the initiative Send a specific frequency signal (active tag, active tag or active tag); after the reader reads and decodes the information, it will be sent to the central information system for relevant data processing.
Passive tags have no internal power source. Its internal integrated circuit is driven by receiving electromagnetic waves emitted by the RFID reader. When the tag receives a signal of sufficient strength, it can send the data to the reader. These data include not only the ID number (unique ID), but also the pre-existing data in the EEPROM in the tag.
Because passive tags have the advantages of low price, small size and no power supply. RFID tags on the market are mainly passive.
Generally speaking, the antenna of a passive tag has two tasks: First, it receives electromagnetic waves from the reader to drive the tag IC. Second: When the tag returns a signal, it needs to be switched by the impedance of the antenna to produce a 0 to 1 change. The problem is that if you want to get the best return efficiency, the antenna impedance must be designed as "open and short", it will completely reflect the signal, and the tag IC cannot receive it. Semi-active tags are designed to solve this problem. The semi-active type is similar to the passive type, but its battery is small and the power supply can drive the tag IC to work. The advantage of this is that the antenna can be used as a return signal without the task of receiving electromagnetic waves. Compared with the passive type, the semi-active type has a faster response speed and higher efficiency.
Different from passive and semi-passive, the active tag itself has an internal power supply to provide the power required by the internal IC to generate external signals. Generally speaking, an active tag has a longer reading distance and a larger storage capacity, and can be used to store some other information sent by the reader. Since the bonded parts will undergo various pressure tests in actual use, we will conduct different tests in the laboratory to ensure the bonding quality. The usual practice is to test RFID tags made with production equipment. The vision system can detect the position of the chip, and the card reader system can test the performance of the tag.