From the perspective of communication and energy sensing methods between RFID card readers and electronic tags, 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 reader can be a read or read/write device according to the structure and technology used, and 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 reader provides energy and timing to the passive transponder 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. 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.
