Handheld rfid computer's working principle

RFID reader (reader writer) communicates wirelessly with RFID electronic tag through antenna, which can read or write tag identification code and memory data. A typical reader consists of a high-frequency module (transmitter and receiver), a control unit, and a reader antenna.

Among them, electronic tags are also called RF tags, transponders and data carriers; Readers are also called readout devices, scanners, communicators and readers (depending on whether the electronic tag can rewrite data wirelessly). The spatial (contactless) coupling of RF signals is realized between the electronic tag and the reader through the coupling element. In the coupling channel, the energy transmission and data exchange are realized according to the time sequence relationship.

There are two types of RF signal coupling between reader and electronic tag.

(1) Inductive coupling. The transformer model is coupled by spatial high-frequency alternating magnetic field, which is based on the law of electromagnetic induction.

(2) Electromagnetic backscatter coupling: radar principle model, the electromagnetic wave emitted is reflected when it meets the target and carries back the target information at the same time, which is based on the spatial propagation law of electromagnetic wave.