The basic working principle of RFID system is as follows: the reader sends radio frequency signal of specific frequency through the transmitting antenna. When the electronic tag enters the effective working area, the induced current is generated, so that the energy is activated and the electronic tag transmits its coded information through the built-in antenna.The receiving antenna of the reader receives the modulated signal sent from the label, which is transmitted to the reader signal processing module by the antenna modulator. After demodulation and decoding, the effective information is transmitted to the background host system for relevant processing.The host system recognizes the identity of the tag according to logical operation, makes corresponding processing and control for different Settings, and finally sends a signal to control the reader to complete different read and write operations.

From the communication and energy induction modes between electronic tags and readers, RFID systems can generally be divided into inductive coupling (magnetic coupling) system and electromagnetic backscattering coupling (electromagnetic coupling) system.The inductance coupling system is realized by the high frequency alternating magnetic field in space, which is based on the law of electromagnetic induction.Electromagnetic back-scattering coupling, namely radar principle model, reflects the electromagnetic wave emitted when it encounters the target, and carries back the target information at the same time, according to the spatial propagation law of electromagnetic wave.

Inductively coupled mode is generally suitable for short distance RFID system with medium and low frequencies.The electromagnetic backscattering coupling mode is generally suitable for high frequency and microwave remote RFID system.