Briefly describe the composition and working principle of RFID

The composition of RFID

The RFID system consists of 5 components, including transmitter, receiver, microprocessor, antenna, and RFID tag (IC card). Transmitters, receivers, and microprocessors are usually packaged together, also known as readers. Therefore, the industry often divides RFID systems into three major components: readers, antennas, and RFID tags (IC Cards), which can generally be produced by different manufacturers.

Working principle of RFID

RFID originated from radar technology, so its working principle is very similar to radar. Firstly, the reader emits an electronic signal through the antenna, and the RFID tag (IC card) receives the signal and transmits the internally stored identification information. The reader then receives and recognizes the information sent back by the RFID tag (IC card) through the antenna, and finally sends the recognition result to the host.

RFID tags (IC Cards) and readers achieve spatial (contactless) coupling of RF signals through coupling elements. Within the coupling channel, energy transfer and data exchange are achieved based on temporal relationships. There are two types of RF signal coupling that occur between readers and RFID tags (IC Cards): one is inductive coupling, a transformer model, which achieves coupling through spatial high-frequency alternating magnetic fields, based on the theory of electromagnetic induction law; Another type is electromagnetic backscatter coupling, radar model, where the emitted electromagnetic waves reflect off the target and carry back target information. The theoretical basis is the propagation characteristics of electromagnetic waves in space.