A complete RFID system is composed of three parts: a reader and an electronic tag which is the so-called transponder and application software system. Its working principle is that the reader transmits a specific frequency radio wave energy to the transponder to drive the transponder circuit to send out the internal data. At this time, the reader will receive the interpretation data in sequence and send it to the application program for corresponding processing.
Based on the communication and energy sensing methods between the RFID chip 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, while higher frequency mostly adopts the second method.
The RFID reader can be a reading or reading/writing device according to the structure and technology, which 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 transponder generally use half-duplex communication for information exchange, and the RFID reader provides energy and timing to the passive transponder through the 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. The transponder is the information carrier of the RFID system. At present, most transponders are passive units composed of coupling elements (coils, microstrip antennas, etc.) and microchips.